Findlaw for Small Business
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Monday, Oct. 6, 2008

                                     LEASE


                                    BETWEEN


                METROPOLITAN LIFE INSURANCE COMPANY (LANDLORD)


                                      AND


                            MAXYGEN, INC. (TENANT)



                                SEAPORT CENTRE

                           Redwood City, California
<PAGE>
 
                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                   PAGE
<S>                                                                                   <C>
ARTICLE ONE - BASIC LEASE PROVISIONS................................................   1
     1.01 BASIC LEASE PROVISIONS....................................................   1
     1.02 ENUMERATION OF EXHIBITS & RIDER(S)........................................   2
     1.03 DEFINITIONS...............................................................   2

ARTICLE TWO - PREMISES, TERM, FAILURE TO GIVE POSSESSION, COMMON AREAS AND PARKING..   6
     2.01 LEASE OF PREMISES.........................................................   6
     2.02 TERM......................................................................   6
     2.03 FAILURE TO GIVE POSSESSION................................................   6
     2.04 AREA OF PREMISES..........................................................   6
     2.05 CONDITION OF PREMISES.....................................................   6
     2.06 COMMON AREAS & PARKING....................................................   6

ARTICLE THREE - RENT................................................................   7

ARTICLE FOUR - OPERATING EXPENSES RENT ADJUSTMENTS AND PAYMENTS.....................   7
     4.01 TENANT'S SHARE OF OPERATING EXPENSES......................................   7
     4.02 RENT ADJUSTMENTS..........................................................   8
     4.03 STATEMENT OF LANDLORD.....................................................   8
     4.04 BOOKS AND RECORDS.........................................................   8
     4.05 TENANT OR LEASE SPECIFIC TAXES............................................   9

ARTICLE FIVE - SECURITY DEPOSIT.....................................................   9

ARTICLE SIX -UTILITIES & SERVICES...................................................   9
     6.01 LANDLORD'S GENERAL SERVICES...............................................   9
     6.02 TENANT TO OBTAIN & PAY DIRECTLY...........................................   9
     6.03 TELEPHONE SERVICES........................................................   9
     6.04 FAILURE OR INTERRUPTION OF UTILITY OR SERVICE.............................  10
     6.05 CHOICE OF SERVICE PROVIDER................................................  10
     6.06 SIGNAGE...................................................................  10

ARTICLE SEVEN - POSSESSION, USE AND CONDITION OF PREMISES...........................  11
     7.01 POSSESSION AND USE OF PREMISES............................................  11
     7.02 HAZARDOUS MATERIAL........................................................  11
     7.03 LANDLORD ACCESS TO PREMISES; APPROVALS....................................  15
     7.04 QUIET ENJOYMENT...........................................................  16

ARTICLE EIGHT - MAINTENANCE.........................................................  16
     8.01 LANDLORD'S MAINTENANCE....................................................  16
     8.02 TENANT'S MAINTENANCE......................................................  16

ARTICLE NINE - ALTERATIONS AND IMPROVEMENTS.........................................  16
     9.01 TENANT ALTERATIONS........................................................  16
     9.02 LIENS.....................................................................  17             

ARTICLE TEN - ASSIGNMENT AND SUBLETTING.............................................  17
     10.01 ASSIGNMENT AND SUBLETTING................................................  17
     10.02 [INTENTIONALLY DELETED]..................................................  18
     10.03 EXCESS RENT..............................................................  18
     10.04 TENANT LIABILITY.........................................................  19
     10.05 ASSUMPTION AND ATTORNMENT................................................  19
     10.06 TRANSFER TO TENANT AFFILIATE.............................................  19

ARTICLE ELEVEN - DEFAULT AND REMEDIES...............................................  19
     11.01 EVENTS OF DEFAULT........................................................  19
     11.02 LANDLORD'S REMEDIES......................................................  20
     11.03 ATTORNEY'S FEES..........................................................  21
     11.04 BANKRUPTCY...............................................................  21
     11.05 LANDLORD'S DEFAULT.......................................................  22

ARTICLE TWELVE - SURRENDER OF PREMISES..............................................  22
     12.01 IN GENERAL...............................................................  22
     12.02 LANDLORD'S RIGHTS........................................................  22

ARTICLE THIRTEEN - HOLDING OVER.....................................................  23
</TABLE> 

                                       i
<PAGE>
 
<TABLE> 
<S>                                                                                   <C> 
ARTICLE FOURTEEN - DAMAGE BY FIRE OR OTHER CASUALTY.................................  23
     14.01 SUBSTANTIAL UNTENANTABILITY..............................................  23
     14.02 INSUBSTANTIAL UNTENANTABILITY............................................  24
     14.03 RENT ABATEMENT...........................................................  24
     14.04 WAIVER OF STATUTORY REMEDIES.............................................  24

ARTICLE FIFTEEN - EMINENT DOMAIN....................................................  24
     15.01 TAKING OF WHOLE OR SUBSTANTIAL PART......................................  24
     15.02 TAKING OF PART...........................................................  24
     15.03 COMPENSATION.............................................................  24

ARTICLE SIXTEEN - INSURANCE.........................................................  25
     16.01 TENANT'S INSURANCE.......................................................  25
     16.02 FORM OF POLICIES.........................................................  25
     16.03 LANDLORD'S INSURANCE.....................................................  25
     16.04 WAIVER OF SUBROGATION....................................................  25
     16.05 NOTICE OF CASUALTY.......................................................  26

ARTICLE SEVENTEEN - WAIVER OF CLAIMS AND INDEMNITY..................................  26
     17.01 WAIVER OF CLAIMS.........................................................  26
     17.02 INDEMNITY BY TENANT......................................................  26

ARTICLE EIGHTEEN - RULES AND REGULATIONS............................................  27
     18.01 RULES....................................................................  27
     18.02 ENFORCEMENT..............................................................  27

ARTICLE NINETEEN - LANDLORD'S RESERVED RIGHTS.......................................  27

ARTICLE TWENTY - ESTOPPEL CERTIFICATE...............................................  27
     20.01 IN GENERAL...............................................................  27
     20.02 ENFORCEMENT..............................................................  28

ARTICLE TWENTY-ONE - RELOCATION OF TENANT...........................................  28

ARTICLE TWENTY-TWO - REAL ESTATE BROKERS............................................  28

ARTICLE TWENTY-THREE - MORTGAGEE PROTECTION.........................................  28
     23.01 SUBORDINATION AND ATTORNMENT.............................................  28
     23.02 MORTGAGEE PROTECTION.....................................................  29

ARTICLE TWENTY-FOUR - NOTICES.......................................................  29

ARTICLE TWENTY-FIVE - EXERCISE FACILITY.............................................  29

ARTICLE TWENTY-SIX - MISCELLANEOUS..................................................  30
     26.01 LATE CHARGES.............................................................  30
     26.02 NO JURY TRIAL; VENUE; JURISDICTION.......................................  30
     26.03 DEFAULT UNDER OTHER LEASE................................................  30
     26.04 OPTION...................................................................  30
     26.05 TENANT AUTHORITY.........................................................  30
     26.06 ENTIRE AGREEMENT.........................................................  31
     26.07 MODIFICATION OF LEASE FOR BENEFIT OF MORTGAGEE...........................  31
     26.08 EXCULPATION..............................................................  31
     26.09 ACCORD AND SATISFACTION..................................................  31
     26.10 LANDLORD'S OBLIGATIONS ON SALE OF BUILDING...............................  31
     26.11 BINDING EFFECT...........................................................  31
     26.12 CAPTIONS.................................................................  31
     26.13 TIME; APPLICABLE LAW; CONSTRUCTION.......................................  31
     26.14 ABANDONMENT..............................................................  31
     26.15 LANDLORD'S RIGHT TO PERFORM TENANT'S DUTIES..............................  32
     26.16 SECURITY SYSTEM..........................................................  32
     26.17 NO LIGHT, AIR OR VIEW EASEMENTS..........................................  32
     26.18 RECORDATION..............................................................  32
     26.19 SURVIVAL.................................................................  32
     26.20 RIDERS...................................................................  32
</TABLE>

                                      ii
<PAGE>
 
                                     LEASE

                                  ARTICLE ONE
                            BASIC LEASE PROVISIONS

1.01 BASIC LEASE PROVISIONS

In the event of any conflict between these Basic Lease Provisions and any other
Lease provision, such other Lease provision shall control.

(1)  BUILDING AND ADDRESS:

     Building with several street addresses, including 200 Saginaw Drive
     Redwood City, California  94063

     Building Number 27, located in Phase II ("Tenant's Phase") of Seaport
     Centre

(2)  LANDLORD AND ADDRESS:

     Metropolitan Life Insurance Company,
     a New York corporation

     Notices to Landlord shall be addressed:

          Metropolitan Life Insurance Company
          c/o Seaport Centre Manager
          701 Chesapeake Drive
          Redwood City, CA 94063

          with copies to the following:

               Metropolitan Life Insurance Company
               400 South El Camino Real, Suite 800
               San Mateo, CA  94402
               Attention:  EIM Manager

(3)  TENANT AND CURRENT ADDRESS:

     (a) Name:                    Maxygen, Inc.
     (b) State of incorporation:  Delaware

     Notices to Tenant shall be addressed:

          Maxygen, Inc.
          515 Galveston Drive
          Redwood City, California  94063
          Attention:  Russell Howard, CEO

(4)  DATE OF LEASE:  as of  April 21, 2000


(5)  LEASE TERM:  sixty months

(6)  PROJECTED COMMENCEMENT DATE:  May 1, 2000, subject to Rider 2

(7)  PROJECTED EXPIRATION DATE:  sixty months after the Commencement Date

(8)  MONTHLY BASE RENT (initial monthly installment due upon Tenant's
     execution):

<TABLE>
<CAPTION>
 
     Period from/to         Monthly     Monthly Rate/SF of Rentable Area
     --------------         -------     --------------------------------
     <S>                    <C>         <C>
 
     Month 01 - Month 12    $31,648.00                $4.000
     Month 13 - Month 24    $33,230.40                $4.200
     Month 25 - Month 36    $34,891.92                $4.410
     Month 37 - Month 48    $36,636.52                $4.631
     Month 49 - Month 60    $38,468.34                $4.862
</TABLE>

(9)  RENT ADJUSTMENT DEPOSIT (initial monthly rate, until further notice):
     $3,481.28 (initial monthly installment due upon Tenant's execution)

(10) RENTABLE AREA OF THE PREMISES:  7,912 square feet
 

                                       1
<PAGE>
 
(11) RENTABLE AREA OF THE BUILDING   32,400 square feet
 
(12) RENTABLE AREA OF THE PHASE:     235,620 square feet
 
(13) RENTABLE AREA OF THE PROJECT:   537,444 square feet

(14) SECURITY DEPOSIT:  Two Hundred and Thirty Thousand Eight Hundred Ten
     Dollars ($230,810.00) due upon Tenant's execution, subject to the terms of
     Article Five

(15) SUITE NUMBER &/OR ADDRESS OF PREMISES:  200 Saginaw Drive
                                             Redwood City, California 94063

(16) TENANT'S SHARE:

          Tenant's Building Share:   24.42%
          Tenant's Phase Share:      03.36%
          Tenant's Project Share:    01.47%

(17) TENANT'S USE OF PREMISES:  General office use, biotechnology research and
     development.

(18) PARKING SPACES:  twenty-five (25)

(19) BROKERS:

     Landlord's Broker:  Cornish & Carey

     Tenant's Broker:    CRESA Partners

1.02 ENUMERATION OF EXHIBITS & RIDER(S)

The Exhibits and Rider(s) set forth below and attached to this Lease are
incorporated in this Lease by this reference:

EXHIBIT A  Plan of Premises
---------                  
EXHIBIT B  Workletter Agreement (intentionally omitted)
---------                                              
EXHIBIT C  Site Plan of Project
---------                      
EXHIBIT D  Permitted Hazardous Materials
---------                               
EXHIBIT E  Hazardous Materials Plans
---------                           

RIDER 1     Commencement Date Agreement
-------                                
RIDER 2     Additional Provisions
-------                          

1.03 DEFINITIONS

For purposes hereof, the following terms shall have the following meanings:

ADJUSTMENT YEAR:  The applicable calendar year or any portion thereof after the
Commencement Date of this Lease for which a Rent Adjustment computation is being
made.

AFFILIATE:  Any Person (as defined below) which is currently owned or controlled
by, owns or controls, or is under common ownership or control with Tenant.  For
purposes of this definition, the word "control," as used above means, with
respect to a Person that is a corporation, the right to exercise, directly or
indirectly, more than sixty percent (60%) of the voting rights attributable to
the shares of the controlled corporation and, with respect to a Person that is
not a corporation, the possession, directly or indirectly, of the power at all
times to direct or cause the direction of the management and policies of the
controlled Person.  The word Person means an individual, partnership, trust,
corporation, firm or other entity.

BUILDING:  The building in which the Premises is located, at the address and
Building number specified in Section 1.01(1).

BUILDING OPERATING EXPENSES:  Those Operating Expenses described in Section
4.01.

COMMENCEMENT DATE:  The date specified in Section 1.01(6) as the Projected
Commencement Date, unless changed by operation of Article Two or Rider 2.

COMMON AREAS:  All areas of the Project made available by Landlord from time to
time for the general common use or benefit of the tenants of the Building or
Project, and their employees and invitees, or the public, as such areas
currently exist and as they may be changed from time to time.

DECORATION:  Tenant Alterations which do not require a building permit and which
do not affect the facade or roof of the Building, or involve any of the
structural elements of the Building, or involve any of the Building's 

                                       2
<PAGE>
 
systems, including its electrical, mechanical, plumbing, security, heating,
ventilating, air-conditioning, communication, and fire and life safety systems.

DEFAULT RATE:  Two (2) percentage points above the rate then most recently
announced by Bank of America N.T.& S.A. at its San Francisco main office as its
corporate base lending rate, from time to time announced, but in no event higher
than the maximum rate permitted by Law.

ENVIRONMENTAL LAWS:  All Laws governing the use, storage, disposal or generation
of any Hazardous Material or pertaining to environmental conditions on, under or
about the Premises or any part of the Project, including the Comprehensive
Environmental Response Compensation and Liability Act of 1980, as amended (42
U.S.C. Section 9601 et seq.), and the Resource Conservation and Recovery Act of
                    -- ---                                                     
1976, as amended (42 U.S.C. Section 6901 et seq.).
                                         -- ---   

EXPIRATION DATE:  The date specified in Section 1.01(7) unless changed by
operation of Article Two.

FORCE MAJEURE:  Any accident, casualty, act of God, war or civil commotion,
strike or labor troubles, or any cause whatsoever beyond the reasonable control
of Landlord, including water shortages, energy shortages or governmental
preemption in connection with an act of God, a national emergency, or by reason
of Law, or by reason of the conditions of supply and demand which have been or
are affected by act of God, war or other emergency.

HAZARDOUS MATERIAL:  Such substances, material and wastes which are or become
regulated under any Environmental Law; or which are classified as hazardous or
toxic or medical waste or biohazardous waste under any Environmental Law; and
explosives, firearms and ammunition, flammable material, radioactive material,
asbestos, polychlorinated biphenyls and petroleum and its byproducts.

INDEMNITEES:  Collectively, Landlord, any Mortgagee or ground lessor of the
Property, the property manager and the leasing manager for the Property and
their respective directors, officers, agents and employees.

LAND:  The parcel(s) of real estate on which the Building and Project are
located.

LANDLORD WORK:  The construction or installation of improvements to be furnished
by Landlord, if any, specifically described in Rider 2 attached hereto.

LAWS OR LAW:  All laws, ordinances, rules, regulations, other requirements,
orders, rulings or decisions adopted or made by any governmental body, agency,
department or judicial authority having jurisdiction over the Property, the
Premises or Tenant's activities at the Premises and any covenants, conditions or
restrictions of record which affect the Property.

LEASE:  This instrument and all exhibits and riders attached hereto, as may be
amended from time to time.

LEASE YEAR:  The twelve month period beginning on the first day of the first
month following the Commencement Date (unless the Commencement Date is the first
day of a calendar month in which case beginning on the Commencement Date), and
each subsequent twelve month, or shorter, period until the Expiration Date.

MONTHLY BASE RENT:  The monthly rent specified in Section 1.01(8).

MORTGAGEE:  Any holder of a mortgage, deed of trust or other security instrument
encumbering the Property.

NATIONAL HOLIDAYS:  New Year's Day, Memorial Day, Independence Day, Labor Day,
Thanksgiving Day and Christmas Day and other holidays recognized by the Landlord
and the janitorial and other unions servicing the Building in accordance with
their contracts.

OPERATING EXPENSES:  All Taxes, costs, expenses and disbursements of every kind
and nature which Landlord shall pay or become obligated to pay in connection
with the ownership, management, operation, maintenance, replacement and repair
of the Property (including the amortized portion of any capital expenditure or
improvement, together with interest thereon, expenses of changing utility
service providers, and any dues, assessments and other expenses pursuant to any
covenants, conditions and restrictions, or any reciprocal easements, or any
owner's association now or hereafter affecting the Project).  Operating Expenses
shall be allocated among the categories of Project Operating Expenses, Building
Operating Expenses or Phase Operating Expenses as provided in Article Four.  If
any Operating Expense, though paid in one year, relates to more than one
calendar year, at the option of Landlord such expense may be proportionately
allocated among such related calendar years.  Operating Expenses shall include
the following, by way of illustration only and not limitation: (1) all Taxes;
(2) all insurance premiums and other costs (including deductibles), including
the cost of rental insurance; (3) all license, permit and inspection fees; (4)
all costs of utilities, fuels and related services, including water, sewer,
light, telephone, power and steam connection, service and related charges; (5)
all costs to repair, maintain and operate heating, ventilating and air
conditioning systems, including preventive maintenance; (6) all janitorial,
landscaping and security services; (7) all wages, salaries, payroll taxes,
fringe benefits and other labor costs, including the cost of 

                                       3
<PAGE>
 
workers' compensation and disability insurance; (8) all costs of operation,
maintenance and repair of all parking facilities and other common areas; (9) all
supplies, materials, equipment and tools; (10) dues, assessments and other
expenses pursuant to any covenants, conditions and restrictions, or any
reciprocal easements, or any owner's association now or hereafter affecting the
Project; (11) modifications to the Building or the Project occasioned by Laws
now or hereafter in effect; (12) the total charges of any independent
contractors employed in the care, operation, maintenance, repair, leasing and
cleaning of the Project, including landscaping, roof maintenance, and repair,
maintenance and monitoring of life-safety systems, plumbing systems, electrical
wiring and Project signage; (13) the cost of accounting services necessary to
compute the rents and charges payable by tenants at the Project; (14) exterior
window and exterior wall cleaning and painting; (15) managerial and
administrative expenses; (16) all costs in connection with the exercise facility
at the Project; (17) all costs and expenses related to Landlord's retention of
consultants in connection with the routine review, inspection, testing,
monitoring, analysis and control of Hazardous Materials, and retention of
consultants in connection with the clean-up of Hazardous Materials (to the
extent not recoverable from a particular tenant of the Project), and all costs
and expenses related to the implementation of recommendations made by such
consultants concerning the use, generation, storage, manufacture, production,
storage, release, discharge, disposal or clean-up of Hazardous Materials on,
under or about the Premises or the Project (to the extent not recoverable from a
particular tenant of the Project); but Operating Costs shall not include the
costs and expenses, including those of retention of consultants and
implementation of such consultant's recommendations, to the extent incurred
specifically to clean-up or remove Hazardous Materials present on, under or
about the Premises or the Project prior to delivery to Tenant of possession of
the Premises; (18) all capital improvements made for the purpose of reducing or
controlling other Operating Expenses, and all other capital expenditures, but
only as amortized over the useful life of the applicable item(s), together with
interest thereon; (19) all property management costs and fees, including all
costs in connection with the Project property management office; and (20) all
fees or other charges incurred in conjunction with voluntary or involuntary
membership in any energy conservation, air quality, environmental, traffic
management or similar organizations. Operating Expenses shall not include: (a)
costs of alterations of space to be occupied by new or existing tenants of the
Project; (b) depreciation charges; (c) interest and principal payments on loans
(except for loans for capital improvements which Landlord is allowed to include
in Operating Expenses as provided above); (d) ground rental payments; (e) real
estate brokerage and leasing commissions; (f) advertising and marketing
expenses; (g) costs of Landlord reimbursed by insurance proceeds; (h) expenses
incurred in negotiating leases of other tenants in the Project or enforcing
lease obligations of other tenants in the Project; and (i) Landlord's or
Landlord's property manager's corporate general overhead or corporate general
administrative expenses.

PHASE:  Phase means any individual Phase of the Project, as more particularly
described in the definition of Project.

PHASE OPERATING EXPENSES:  Those Operating Expenses described in Section 4.01.

PREMISES:  The space located in the Building at the Suite Number listed in
Section 1.01(15) and depicted on Exhibit A attached hereto.
                                 ---------                 

PROJECT or PROPERTY:  As of the date hereof, the Project is known as Seaport
Centre and consists of those buildings (including the Building) whose general
location is shown on the Site Plan of the Project attached as Exhibit C, located
                                                              ---------         
in Redwood City, California, associated vehicular and parking areas, landscaping
and improvements, together with the Land, any associated interests in real
property, and the personal property, fixtures, machinery, equipment, systems and
apparatus located in or used in conjunction with any of the foregoing.  The
Project may also be referred to as the Property.  As of the date hereof, the
Project is divided into Phase I and Phase II, which are generally designated on
Exhibit C, each of which may individually be referred to as a Phase.  Landlord
---------                                                                     
reserves the right from time to time to add or remove buildings, areas and
improvements to or from a Phase or the Project, or to add or remove a Phase to
or from the Project.  In the event of any such addition or removal which affects
Rentable Area of the Project or a Phase, Landlord shall make a corresponding
recalculation and adjustment of any affected Rentable Area and Tenant's Share.

PROJECT OPERATING EXPENSES:  Those Operating Expenses described in Section 4.01.

REAL PROPERTY:  The Property excluding any personal property.

RENT:  Collectively, Monthly Base Rent, Rent Adjustments and Rent Adjustment
Deposits, and all other charges, payments, late fees or other amounts required
to be paid by Tenant under this Lease.

RENT ADJUSTMENT:  Any amounts owed by Tenant for payment of Operating Expenses.
The Rent Adjustments shall be determined and paid as provided in Article Four.

RENT ADJUSTMENT DEPOSIT:  An amount equal to Landlord's estimate of the Rent
Adjustment attributable to each month of the applicable Adjustment Year.  On or
before the Commencement Date and the beginning of each subsequent Adjustment
Year or with Landlord's Statement (defined in Article Four), Landlord may
estimate and notify Tenant in writing of its estimate of Operating Expenses,
including Project Operating Expenses, Building Operating Expenses and Phase
Operating Expenses, and Tenant's Share of each, for the applicable Adjustment
Year.  The Rent Adjustment Deposit applicable for the calendar year in which the
Commencement Date occurs shall be the amount, if any, specified in Section
1.01(9).  Nothing 

                                       4
<PAGE>
 
contained herein shall be construed to limit the right of Landlord from time to
time during any calendar year to revise its estimates of Operating Expenses and
to notify Tenant in writing thereof and of revision by prospective adjustments
in Tenant's Rent Adjustment Deposit payable over the remainder of such year. The
last estimate by Landlord shall remain in effect as the applicable Rent
Adjustment Deposit unless and until Landlord notifies Tenant in writing of a
change.

RENTABLE AREA OF THE BUILDING:  The amount of square footage set forth in
Section 1.01(11)

RENTABLE AREA OF THE PHASE:  The amount of square footage set forth in Section
1.01(12)

RENTABLE AREA OF THE PREMISES:  The amount of square footage set forth in
Section 1.01(10).

RENTABLE AREA OF THE PROJECT:  The amount of square footage set forth in Section
1.01(13), which represents the sum of the rentable area of all space intended
for occupancy in the Project.

SECURITY DEPOSIT:  The funds specified in Section 1.01(14), if any, deposited by
Tenant with Landlord as security for Tenant's performance of its obligations
under this Lease.

SUBSTANTIALLY COMPLETE:  The completion of the Landlord Work or Tenant Work, as
the case may be, except for minor insubstantial details of construction,
decoration or mechanical adjustments which remain to be done.

TAXES:  All federal, state and local governmental taxes, assessments (including
assessment bonds) and charges  of every kind or nature, whether general,
special, ordinary or extraordinary, which Landlord shall pay or become obligated
to pay because of or in connection with the ownership, leasing, management,
control or operation of the Property or any of its components (including any
personal property used in connection therewith), which may also include any
rental or similar taxes levied in lieu of or in addition to general real and/or
personal property taxes.  For purposes hereof, Taxes for any year shall be Taxes
which are assessed for any period of such year, whether or not such Taxes are
billed and payable in a subsequent calendar year.  There shall be included in
Taxes for any year the amount of all fees, costs and expenses (including
reasonable attorneys' fees) paid by Landlord during such year in seeking or
obtaining any refund or reduction of Taxes.  Taxes for any year shall be reduced
by the net amount of any tax refund received by Landlord attributable to such
year.  If a special assessment payable in installments is levied against any
part of the Property, Taxes for any year shall include only the installment of
such assessment and any interest payable or paid during such year.  Taxes shall
not include any federal or state inheritance, general income, gift or estate
taxes, except that if a change occurs in the method of taxation resulting in
whole or in part in the substitution of any such taxes, or any other assessment,
for any Taxes as above defined, such substituted taxes or assessments shall be
included in the Taxes.

TENANT ADDITIONS:  Collectively, Landlord Work, Tenant Work and Tenant
Alterations.

TENANT ALTERATIONS:  Any alterations, improvements, additions, installations or
construction in or to the Premises or any Real Property systems serving the
Premises done or caused to be done by Tenant after the date hereof, whether
prior to or after the Commencement Date (including Tenant Work, but excluding
Landlord Work).

TENANT DELAY:  Any event or occurrence which delays the completion of the
Landlord Work which is caused by or is described as follows:

     (i)   special work, changes, alterations or additions requested or made by
     Tenant in the design or finish in any part of the Premises after approval
     of the plans and specifications (as described in the Rider 2);

     (ii)  Tenant's delay in submitting plans, supplying information, approving
     plans, specifications or estimates, giving authorizations or otherwise;

     (iii) failure to approve and pay for such work as Landlord undertakes to
     complete at Tenant's expense;

     (iv)  the performance or completion by Tenant or any person engaged by
     Tenant of any work in or about the Premises; or

     (v)   failure to perform or comply with any obligation or condition binding
     upon Tenant pursuant to Rider 2, including the failure to approve and pay
     for such Landlord Work or other items if and to the extent Rider 2 provides
     they are to be approved or paid by Tenant.

TENANT WORK:  All work installed or furnished to the Premises by Tenant in
connection with Tenant's initial occupancy pursuant to Rider 2.

TENANT'S BUILDING SHARE:  The share as specified in Section 1.01(16) and Section
4.01.

TENANT'S PHASE:  The Phase in which the Premises is located, as indicated in
Section 1.01(1).

                                       5
<PAGE>
 
TENANT'S PHASE SHARE:  The share as specified in Section 1.01(16) and Section
4.01.

TENANT'S PROJECT SHARE:  The share as specified in Section 1.01(16) and Section
4.01.

TENANT'S SHARE:  Shall mean collectively, Tenant's respective shares of the
respective categories of Operating Expenses, as provided in Section 1.01(16) and
Section 4.01.

TERM:  The term of this Lease commencing on the Commencement Date and expiring
on the Expiration Date.

TERMINATION DATE:  The Expiration Date or such earlier date as this Lease
terminates or Tenant's right to possession of the Premises terminates.

WORKLETTER:  (intentionally omitted)

                                  ARTICLE TWO
     PREMISES, TERM, FAILURE TO GIVE POSSESSION, COMMON AREAS AND PARKING

2.01 LEASE OF PREMISES

Landlord hereby leases to Tenant and Tenant hereby leases from Landlord the
Premises for the Term and upon the terms, covenants and conditions provided in
this Lease.

2.02 TERM

The Commencement Date shall be the date determined pursuant to Rider 2.

2.03 FAILURE TO GIVE POSSESSION

(intentionally omitted; see Rider 2)

2.04 AREA OF PREMISES

Landlord and Tenant agree that for all purposes of this Lease the Rentable Area
of the Premises, the Rentable Area of the Building, the Rentable Area of the
Phase and the Rentable Area of the Project as set forth in Article One are
controlling, and are not subject to revision after the date of this Lease,
except as otherwise provided herein.

2.05 CONDITION OF PREMISES

(intentionally omitted; see Rider 2)

2.06 COMMON AREAS & PARKING

     (a) Right to Use Common Areas.  Tenant shall have the non-exclusive right,
         -------------------------                                             
in common with others, to the use of any common entrances, ramps, drives and
similar access and serviceways and other Common Areas in the Project.  The
rights of Tenant hereunder in and to the Common Areas shall at all times be
subject to the rights of Landlord and other tenants and owners in the Project
who use the same in common with Tenant, and it shall be the duty of Tenant to
keep all the Common Areas free and clear of any obstructions created or
permitted by Tenant or resulting from Tenant's operations.  Tenant shall not use
the Common Areas or common facilities of the Building or the Project, including
the Building's electrical room, parking lot or trash enclosures, for storage
purposes.  Nothing herein shall affect the right of Landlord at any time to
remove any persons not authorized to use the Common Areas or common facilities
from such areas or facilities or to prevent their use by unauthorized persons.

     (b) Changes in Common Areas.  Landlord reserves the right, at any time and
         -----------------------                                               
from time to time to (i) make alterations in or additions to the Common Areas or
common facilities of the Project, including constructing new buildings or
changing the location, size, shape or number of the driveways, entrances,
parking spaces, parking areas, loading and unloading areas, landscape areas and
walkways, (ii) designate property to be included in or eliminate property from
the Common Areas or common facilities of the Project, (iii) close temporarily
any of the Common Areas or common facilities of the Project for maintenance
purposes, and (4) use the Common Areas and common facilities of the Project
while engaged in making alterations in or additions and repairs to the Project;
provided, however, that reasonable access to the Premises and parking at or near
the Project remains available.

     (c) Parking.  During the Term, Tenant shall have the right to use the
         -------                                                          
number of Parking Spaces specified in Section 1.01(18) for parking on an
unassigned basis on that portion of the Project designated by Landlord from time
to time for parking.  Tenant acknowledges and agrees that the parking spaces in
the Project's parking facility may include a mixture of spaces for compact
vehicles as well as full-size passenger automobiles, and that Tenant shall not
use parking spaces for vehicles larger than the striped size of the parking
spaces.  Tenant shall not park any vehicles at the Project overnight.  Tenant
shall comply with any 

                                       6
<PAGE>
 
and all parking rules and regulations if and as from time to time established by
Landlord. Tenant shall not allow any vehicles using Tenant's parking privileges
to be parked, loaded or unloaded except in accordance with this Section,
including in the areas and in the manner designated by Landlord for such
activities. If any vehicle is using the parking or loading areas contrary to any
provision of this Section, Landlord shall have the right, in addition to all
other rights and remedies of Landlord under this Lease, to remove or tow away
the vehicle without prior notice to Tenant, and the cost thereof shall be paid
to Landlord within ten (10) days after notice from Landlord to Tenant.

                                 ARTICLE THREE
                                     RENT

Tenant agrees to pay to Landlord at the first office specified in Section
1.01(2), or to such other persons, or at such other places designated by
Landlord, without any prior demand therefor in immediately available funds and
without any deduction or offset whatsoever, Rent, including Monthly Base Rent
and Rent Adjustments in accordance with Article Four, during the Term. Monthly
Base Rent shall be paid monthly in advance on the first day of each month of the
Term, except that the first installment of Monthly Base Rent shall be paid by
Tenant to Landlord concurrently with execution of this Lease.  Monthly Base Rent
shall be prorated for partial months within the Term.  Unpaid Rent shall bear
interest at the Default Rate from the date due until paid.  Tenant's covenant to
pay Rent shall be independent of every other covenant in this Lease.

                                 ARTICLE FOUR
               OPERATING EXPENSES, RENT ADJUSTMENTS AND PAYMENTS

4.01 TENANT'S SHARE OF OPERATING EXPENSES

Tenant shall pay Tenant's Share of Operating Expenses in the respective shares
of the respective categories of Operating Expenses as set forth below.

          (a)  Tenant's Project Share of Project Operating Expenses, which is
     the percentage obtained by dividing the rentable square footage of the
     Premises for the building(s) in which the Premises is located by the
     rentable square footage of the Project and as of the date hereof equals the
     percentage set forth in Section 1.01(16);

          (b)  Tenant's Building Share of Building Operating Expenses, which is
     the percentage obtained by dividing the rentable square footage of the
     Premises respectively for each building in which the Premises is located by
     the total rentable square footage of such building and as of the date
     hereof equals the percentage set forth in Section 1.01(16);

          (c)  Tenant's Phase Share of Phase Operating Expenses, which is the
     percentage obtained by dividing the aggregate rentable square footage of
     the Premises located in Tenant's Phase by the total rentable square footage
     of Tenant's Phase and as of the date hereof equals the percentage set forth
     in Section 1.01(16);

          (d)  Project Operating Expenses shall mean all Operating Expenses that
     are not included as Phase Operating Expenses (defined below) and that are
     not either Building Operating Expenses or operating expenses directly and
     separately identifiable to the operation, maintenance or repair of any
     other building located in the Project, but Project Operating Expenses
     includes operating expenses allocable to any areas of the Building or any
     other building during such time as such areas are made available by
     Landlord for the general common use or benefit of all tenants of the
     Project, and their employees and invitees, or the public, as such areas
     currently exist and as they may be changed from time to time;

          (e)  Building Operating Expenses shall mean Operating Expenses that
     are directly and separately identifiable to each building and only such
     building(s) in which the Premises or part thereof is located.  Building(s)
     in which the Premises or any part thereof are not located shall not be
     included in determining Building Operating Expenses;

          (f)  Phase Operating Expenses shall mean Operating Expenses that
     Landlord may allocate to a Phase as directly and separately identifiable to
     all buildings located in the Phase (including but not limited to the
     Building) and may include Project Operating Expenses that are separately
     identifiable to a Phase;

          (g)  Landlord shall have the right to allocate a particular item or
     portion of Operating Expenses as any one of Project Operating Expenses,
     Building Operating Expenses or Phase Operating Expenses; however, in no
     event shall any portion of Building Operating Expenses, Project Operating
     Expenses or Phase Operating Expenses be assessed or counted against Tenant
     more than once; and.

          (h)  Notwithstanding anything to the contrary contained in this
     Section 4.01, as to each specific category of Operating Expense which one
     or more tenants of the Building either pays directly to third parties or
     specifically reimburses to Landlord (for example, separately contracted
     janitorial services or property taxes directly reimbursed to Landlord),
     then, on a category by category

                                       7
<PAGE>
 
     basis, the amount of Operating Expenses for the affected period shall be
     adjusted as follows: (1) all such tenant payments with respect to such
     category of expense and all of Landlord's costs reimbursed thereby shall be
     excluded from Operating Expenses and Tenant's Building Share, Tenant's
     Phase Share or Tenant's Project Share, as the case may be, for such
     category of Operating Expense shall be adjusted by excluding the square
     footage of all such tenants, and (2) if Tenant pays or directly reimburses
     Landlord for such category of Operating Expense, such category of Operating
     Expense shall be excluded from the determination of Operating Expenses for
     the purposes of this Lease.

4.02 RENT ADJUSTMENTS

Tenant shall pay to Landlord Rent Adjustments with respect to each Adjustment
Year as follows:

          (a)  The Rent Adjustment Deposit representing Tenant's Share of
     Landlord's estimate of Operating Expenses, as described in Section 4.01,
     for the applicable Adjustment Year (or portion thereof) monthly during the
     Term with the payment of Monthly Base Rent, except the first installment
     which shall be paid by Tenant to Landlord concurrently with execution of
     this Lease; and

          (b)  Any Rent Adjustments due in excess of the Rent Adjustment
     Deposits in accordance with Section 4.02.

4.03 STATEMENT OF LANDLORD

Within one hundred twenty (120) days after the end of each calendar year or as
soon thereafter as reasonably possible, Landlord will furnish Tenant a statement
("Landlord's Statement") showing the following:

          (a)  Operating Expenses for the last Adjustment Year showing in
     reasonable detail the actual Operating Expenses categorized among Project
     Operating Expenses, Building Operating Expenses and Phase Operating
     Expenses for such period and Tenant's Share of each as described in Section
     4.01 above;

          (b)  The amount of Rent Adjustments due Landlord for the last
     Adjustment Year, less credit for Rent Adjustment Deposits paid, if any; and

          (c)  Any change in the Rent Adjustment Deposit due monthly in the
     current Adjustment Year, including the amount or revised amount due for
     months preceding any such change pursuant to Landlord's Statement.

Tenant shall pay to Landlord within thirty (30) days after receipt of such
statement any amounts for Rent Adjustments then due in accordance with
Landlord's Statement.  Any amounts due from Landlord to Tenant pursuant to this
Section shall be credited to the Rent Adjustment Deposit next coming due, or
refunded to Tenant if the Term has already expired provided Tenant is not in
default hereunder.  No interest or penalties shall accrue on any amounts which
Landlord is obligated to credit or refund to Tenant by reason of this Section
4.02.  Landlord's failure to deliver Landlord's Statement or to compute the
amount of the Rent Adjustments shall not constitute a waiver by Landlord of its
right to deliver such items nor constitute a waiver or release of Tenant's
obligations to pay such amounts.  The Rent Adjustment Deposit shall be credited
against Rent Adjustments due for the applicable Adjustment Year.  During the
last complete calendar year or during any partial calendar year in which the
Lease terminates, Landlord may include in the Rent Adjustment Deposit its
estimate of Rent Adjustments which may not be finally determined until after the
termination of this Lease.  Tenant's obligation to pay Rent Adjustments survives
the expiration or termination of the Lease.  Notwithstanding the foregoing, in
no event shall the sum of Monthly Base Rent and the Rent Adjustments be less
than the Monthly Base Rent payable.

4.04 BOOKS AND RECORDS

Landlord shall maintain books and records showing Operating Expenses and Taxes
in accordance with sound accounting and management practices, consistently
applied.  The Tenant or its representative shall have the right, for a period of
ninety (90) days following the date upon which Landlord's Statement is delivered
to Tenant, to examine the Landlord's books and records with respect to the items
in the foregoing statement of Operating Expenses and Taxes during normal
business hours, upon written notice, delivered at least three (3) business days
in advance. If Tenant does not object in writing to Landlord's Statement within
ninety (90) days of Tenant's receipt thereof, specifying the nature of the item
in dispute and the reasons therefor, then Landlord's Statement shall be
considered final and accepted by Tenant.  Any amount due to the Landlord as
shown on Landlord's Statement, whether or not disputed by Tenant as provided
herein shall be paid by Tenant when due as provided above, without prejudice to
any such written exception.

4.05 TENANT OR LEASE SPECIFIC TAXES

In addition to Monthly Base Rent, Rent Adjustments, Rent Adjustment Deposits and
other charges to be paid by Tenant, Tenant shall pay to Landlord, upon demand,
any and all taxes payable by Landlord (other than federal or state inheritance,
general income, gift or estate taxes) whether or not now customary or within the
contemplation of the parties hereto:  (a) upon, allocable to, or measured by the
Rent payable hereunder, 

                                       8
<PAGE>
 
including any gross receipts tax or excise tax levied by any governmental or
taxing body with respect to the receipt of such rent; or (b) upon or with
respect to the possession, leasing, operation, management, maintenance,
alteration, repair, use or occupancy by Tenant of the Premises or any portion
thereof; or (c) upon the measured value of Tenant's personal property or trade
fixtures located in the Premises or in any storeroom or any other place in the
Premises or the Property, or the areas used in connection with the operation of
the Property, it being the intention of Landlord and Tenant that, to the extent
possible, Tenant shall cause such taxes on personal property or trade fixtures
to be billed to and paid directly by Tenant; (d) resulting from Landlord Work,
Tenant Work or Tenant Alterations to the Premises, whether title thereto is in
Landlord or Tenant; or (e) upon this transaction. Taxes paid by Tenant pursuant
to this Section 4.05 shall not be included in any computation of Taxes as part
of Operating Expenses.

                                 ARTICLE FIVE
                               SECURITY DEPOSIT

Tenant concurrently with the execution of this Lease shall pay to Landlord in
immediately available funds the Security Deposit.  The Security Deposit may be
applied by Landlord to cure, in whole or part, any default of Tenant under this
Lease, and upon notice by Landlord of such application, Tenant shall replenish
the Security Deposit in full by paying to Landlord within ten (10) days of
demand the amount so applied.  Landlord's application of the Security Deposit
shall not constitute a waiver of Tenant's default to the extent that the
Security Deposit does not fully compensate Landlord for all losses, damages,
costs and expenses incurred by Landlord in connection with such default and
shall not prejudice any other rights or remedies available to Landlord under
this Lease or by Law.  Landlord shall not pay any interest on the Security
Deposit.  Landlord shall not be required to keep the Security Deposit separate
from its general accounts.  The Security Deposit shall not be deemed an advance
payment of Rent, nor a measure of damages for any default by Tenant under this
Lease, nor shall it be a bar or defense of any action which Landlord may at any
time commence against Tenant.  In the absence of evidence satisfactory to
Landlord of an assignment of the right to receive the Security Deposit or the
remaining balance thereof, Landlord may return the Security Deposit to the
original Tenant, regardless of one or more assignments of this Lease.  Upon the
transfer of Landlord's interest under this Lease, Landlord's obligation to
Tenant with respect to the Security Deposit shall terminate upon transfer to the
transferee of the Security Deposit, or any balance thereof and the assumption by
the transferee of Landlord's obligations with respect thereto.  If Tenant shall
fully and faithfully comply with all the terms, provisions, covenants, and
conditions of this Lease, the Security Deposit, or any balance thereof, shall be
returned to Tenant within thirty (30) days after Landlord recovers possession of
the Premises.  Tenant hereby waives any and all rights of Tenant under the
provisions of Section 1950.7 of the California Civil Code or other Law regarding
security deposits.

                                  ARTICLE SIX
                             UTILITIES & SERVICES

6.01 LANDLORD'S GENERAL SERVICES

Landlord shall provide maintenance and services as provided in Article Eight.

6.02 TENANT TO OBTAIN & PAY DIRECTLY

     (a) Tenant shall be responsible for and shall pay promptly all charges for
gas, electricity, sewer, heat, light, power, telephone, refuse pickup (to be
performed on a regularly scheduled basis so that accumulated refuse does not
exceed the capacity of Tenant's refuse bins), janitorial service and all other
utilities, materials and services furnished directly to or used by Tenant in, on
or about the Premises, together with all taxes thereon.  Tenant shall contract
directly with the providing companies for such utilities and services.

     (b) Notwithstanding any provision of the Lease to the contrary, without, in
each instance, the prior written consent of Landlord which response for such
consent shall not be unreasonably delayed, as more particularly provided in
Article Nine, Tenant shall not:  (i) make any alterations or additions to the
electric or gas equipment or systems or other Building systems.  If Landlord
does not consent to such request, Landlord shall indicate the reasons therefor.
Tenant's use of electric current shall at no time exceed the capacity of the
wiring, feeders and risers providing electric current to the Premises or the
Building.  The consent of Landlord to the installation of electric equipment
shall not relieve Tenant from the obligation to limit usage of electricity to no
more than such capacity.

6.03 TELEPHONE SERVICES

All telegraph, telephone, and communication connections which Tenant may desire
outside the Premises shall be subject to Landlord's prior written approval, in
Landlord's sole discretion, and the location of all wires and the work in
connection therewith shall be performed by contractors approved by Landlord and
shall be subject to the direction of Landlord, except that such approval is not
required as to Tenant's cabling from the Premises in a route designated by
Landlord to any telephone cabinet or panel provided for Tenant's connection to
the telephone cable serving the Building, so long as Tenant's equipment does not
require connections different than or additional to those to the telephone
cabinet or panel provided.  As to any such connections or work outside the
Premises requiring Landlord's approval, Landlord reserves the right to designate
and control the entity or entities providing telephone or other communication
cable installation, 

                                       9
<PAGE>
 
removal, repair and maintenance outside the Premises and to restrict and control
access to telephone cabinets or panels. In the event Landlord designates a
particular vendor or vendors to provide such cable installation, removal, repair
and maintenance for the Building, Tenant agrees to abide by and participate in
such program. Tenant shall be responsible for and shall pay all costs incurred
in connection with the installation of telephone cables and communication wiring
in the Premises, including any hook-up, access and maintenance fees related to
the installation of such wires and cables in the Premises and the commencement
of service therein, and the maintenance thereafter of such wire and cables; and
there shall be included in Operating Expenses for the Building all installation,
removal, hook-up or maintenance costs incurred by Landlord in connection with
telephone cables and communication wiring serving the Building which are not
allocable to any individual users of such service but are allocable to the
Building generally. If Tenant fails to maintain all telephone cables and
communication wiring in the Premises and such failure affects or interferes with
the operation or maintenance of any other telephone cables or communication
wiring serving the Building, Landlord or any vendor hired by Landlord may enter
into and upon the Premises forthwith and perform such repairs, restorations or
alterations as Landlord deems necessary in order to eliminate any such
interference (and Landlord may recover from Tenant all of Landlord's costs in
connection therewith). No later than the Termination Date, Tenant agrees to
remove all telephone cables and communication wiring installed by Tenant for and
during Tenant's occupancy, which Landlord shall request Tenant to remove. Tenant
agrees that neither Landlord nor any of its agents or employees shall be liable
to Tenant, or any of Tenant's employees, agents, customers or invitees or anyone
claiming through, by or under Tenant, for any damages, injuries, losses,
expenses, claims or causes of action because of any interruption, diminution,
delay or discontinuance at any time for any reason in the furnishing of any
telephone or other communication service to the Premises and the Building.

6.04 FAILURE OR INTERRUPTION OF UTILITY OR SERVICE

To the extent that any equipment or machinery furnished or maintained by
Landlord outside the Premises is used in the delivery of utilities directly
obtained by Tenant pursuant to Section 6.02 and breaks down or ceases to
function properly, Landlord shall use reasonable diligence to repair same
promptly.  In the event of any failure, stoppage or interruption of, or change
in, any utilities or services supplied by Landlord which are not directly
obtained by Tenant, Landlord shall use reasonable diligence to have service
promptly resumed.  In either event covered by the preceding two sentences, if
the cause of any such failure, stoppage or interruption of, or change in,
utilities or services is within the control of a public utility, other public or
quasi-public entity, or utility provider outside Landlord's control,
notification to such utility or entity of such failure, stoppage or interruption
and request to remedy the same shall constitute "reasonable diligence" by
Landlord to have service promptly resumed.  Notwithstanding any other provision
of this Section to the contrary, in the event of any failure, stoppage or
interruption of, or change in, any utility or other service furnished to the
Premises or the Project resulting from any cause, including changes in service
provider or Landlord's compliance with any voluntary or similar governmental or
business guidelines now or hereafter published or any requirements now or
hereafter established by any governmental agency, board or bureau having
jurisdiction over the operation of the Property:  (a) Landlord shall not be
liable for, and Tenant shall not be entitled to, any abatement or reduction of
Rent; (b) no such failure, stoppage, or interruption of any such utility or
service shall constitute an eviction of Tenant or relieve Tenant of the
obligation to perform any covenant or agreement of this Lease to be performed by
Tenant; (c) Landlord shall not be in breach of this Lease nor be liable to
Tenant for damages or otherwise.

6.05  CHOICE OF SERVICE PROVIDER

Tenant acknowledges that Landlord may, at Landlord's sole option, to the extent
permitted by applicable law, elect to change, from time to time, the company or
companies which provide services (including electrical service, gas service,
water, telephone and technical services) to the Property, the Premises and/or
its occupants.  Notwithstanding anything to the contrary set forth in this
Lease, Tenant acknowledges that Landlord has not and does not make any
representations or warranties concerning the identity or identities of the
company or companies which provide services to the Property and the Premises or
its occupants and Tenant acknowledges that the choice of service providers and
matters concerning the engagement and termination thereof shall be solely that
of Landlord. The foregoing provision is not intended to modify, amend, change or
otherwise derogate any provision of this Lease concerning the nature or type of
service to be provided or any specific information concerning the amount thereof
to be provided. Tenant agrees to cooperate with Landlord and each of its service
providers in connection with any change in service or provider.

6.06 SIGNAGE

Tenant shall not install any signage within the Project, the Building or the
Premises without obtaining the prior written approval of Landlord, and Tenant
shall be responsible for the installation and maintenance of any such signage
installed by Tenant.  Any such signage shall comply with Landlord's current
Project signage criteria and all Laws.

                                       10
<PAGE>
 
                                 ARTICLE SEVEN
                   POSSESSION, USE AND CONDITION OF PREMISES


7.01 POSSESSION AND USE OF PREMISES

     (a) Tenant shall occupy and use the Premises only for the uses specified in
Section 1.01(17) to conduct Tenant's business.  Tenant shall not occupy or use
the Premises (or permit the use or occupancy of the Premises) for any purpose or
in any manner which: (1) is unlawful or in violation of any Law or Environmental
Law; (2) may be dangerous to persons or property or which may increase the cost
of, or invalidate, any policy of insurance carried on the Building or covering
its operations; (3) is contrary to or prohibited by the terms and conditions of
this Lease or the rules and regulations as provided in Article Eighteen; (4)
contrary to or prohibited by the articles, bylaws or rules of any owner's
association affecting the Project; (5) is improper, immoral, or objectionable;
(6) would obstruct or interfere with the rights of other tenants or occupants of
the Building or the Project, or injure or annoy them, or would tend to create or
continue a nuisance; or (7) would constitute any waste in or upon the Premises
or Project.

     (b) Landlord and Tenant acknowledge that the Americans With Disabilities
Act of 1990 (42 U.S.C. (S)12101 et seq.) and regulations and guidelines
promulgated thereunder, as all of the same may be amended and supplemented from
time to time (collectively referred to herein as the "ADA") establish
requirements for business operations, accessibility and barrier removal, and
that such requirements may or may not apply to the Premises, the Building and
the Project depending on, among other things: (1) whether Tenant's business is
deemed a "public accommodation" or "commercial facility", (2) whether such
requirements are "readily achievable", and (3) whether a given alteration
affects a "primary function area" or triggers "path of travel" requirements.
The parties hereby agree that: (a) Landlord shall be responsible for ADA Title
III compliance in the Common Areas, except as provided below, (b) Tenant shall
be responsible for ADA Title III compliance in the Premises, including any
leasehold improvements or other work to be performed in the Premises under or in
connection with this Lease, (c) Landlord may perform, or require that Tenant
perform, and Tenant shall be responsible for the cost of, ADA Title III "path of
travel" requirements triggered by Tenant Additions in the Premises, and (d)
Landlord may perform, or require Tenant to perform, and Tenant shall be
responsible for the cost of, ADA Title III compliance in the Common Areas
necessitated by the Building being deemed to be a "public accommodation" instead
of a "commercial facility" as a result of Tenant's use of the Premises.  Tenant
shall be solely responsible for requirements under Title I of the ADA relating
to Tenant's employees.

     (c) Landlord and Tenant agree to cooperate and use commercially reasonable
efforts to participate in traffic management programs generally applicable to
businesses located in or about the area and Tenant shall encourage and support
van and car pooling by, and staggered and flexible working hours for, its office
workers and service employees to the extent reasonably permitted by the
requirements of Tenant's business.  Neither this Section or any other provision
of this Lease is intended to or shall create any rights or benefits in any other
person, firm, company, governmental entity or the public.

     (d) Tenant agrees to cooperate with Landlord and to comply with any and all
guidelines or controls concerning energy management imposed upon Landlord by
federal or state governmental organizations or by any energy conservation
association to which Landlord is a party or which is applicable to the Building.

7.02 HAZARDOUS MATERIAL

     (a) Tenant shall not use, generate, manufacture, produce, store, release,
discharge, or dispose of, on, under or about the Premises or any part of the
Project, or transport to or from the Premises or any part of the Project, any
Hazardous Material or allow its employees, agents, contractors, licensees,
invitees or any other person or entity to do so.  Notwithstanding the foregoing,
Tenant shall be permitted to use and store in, and transport to and from, the
Premises the Hazardous Material identified on Exhibit D hereto and by this
                                              ---------                   
reference incorporated herein ("Permitted Hazardous Material") so long as: (a)
each item of the Permitted Hazardous Material is used or stored in, or
transported to and from, the Premises only to the extent necessary for Tenant's
operation of its business at the Premises; (b) at no time shall any Permitted
Hazardous Material be in use or storage at the Premises in excess of the
quantity specified therefor in Exhibit D; and (c) the conditions set forth in
                               ---------                                     
this Section 7.02 are strictly complied with. The right to use and store in, and
transport to and from, the Premises the Permitted Hazardous Material is personal
to Maxygen, Inc.  and may not be assigned or otherwise transferred by Maxygen,
Inc., without the prior written consent of Landlord, which consent may be
withheld in Landlord's sole discretion. Any consent by Landlord pursuant to
Article Ten of this Lease to an assignment, transfer, subletting, mortgage,
pledge, hypothecation or encumbrance of this Lease, and any interest therein or
right or privilege appurtenant thereto, shall not constitute consent by Landlord
to the use or storage at, or transportation to, the Premises of any Hazardous
Material (including a Permitted Hazardous Material) by any such assignee,
sublessee or transferee unless Landlord expressly agrees otherwise in writing.
Any consent by Landlord to the use or storage at, or transportation to or from
the Premises, of any Hazardous Material (including a Permitted Hazardous
Material) by an assignee, sublessee or transferee of Tenant shall not constitute
a waiver of Landlord's right to refuse such consent as to any subsequent
assignee or transferee.

                                       11
<PAGE>
 
     (b)  Tenant shall comply with and shall cause Tenant's employees, agents,
contractors, licensees, invitees or any other person or entity for whom Tenant
is responsible (collectively, "Tenant's Agents") to comply with, and shall keep
and maintain the Premises and cause Tenant's Agents to keep and maintain the
Premises, in compliance with all Environmental Laws. Neither Tenant nor Tenant's
Agents shall violate, or cause or permit the Premises to be in violation of, any
Environmental Laws.

          Tenant shall, at its own expense prior to Tenant's use and occupancy,
procure, maintain in effect and comply with all conditions of any and all
permits, licenses and other governmental and regulatory approvals required for
Tenant's use of the Premises. Tenant shall cause any and all Hazardous Material
removed from the Premises to be removed and transported solely by duly licensed
handlers to duly licensed facilities for final disposal of such materials and
wastes. Tenant acknowledges that the sewer piping at the Project is made of ABS
plastic. Accordingly, without Landlord's prior written consent, which may be
given or withheld in Landlord's sole discretion, only ordinary domestic sewage
is permitted to be put into the drains at the Premises. UNDER NO CIRCUMSTANCES
SHALL TENANT EVER DEPOSIT ANY ESTERS OR KETONES (USUALLY FOUND IN SOLVENTS TO
CLEAN UP PETROLEUM PRODUCTS) IN THE DRAINS AT THE PREMISES. If Tenant desires to
put any substances other than ordinary domestic sewage into the drains, it shall
first submit to Landlord a complete description of each such substance,
including its chemical composition, and a sample of such substance suitable for
laboratory testing. Landlord shall promptly determine whether or not the
substance can be deposited into the drains and its determination shall be
absolutely binding on Tenant. Upon demand, Tenant shall reimburse Landlord for
expenses incurred by Landlord in making such determination. If any substances
not so approved hereunder are deposited in the drains in Tenant's Premises,
Tenant shall be liable to Landlord for all damages resulting therefrom,
including, but not limited to, all costs and expenses incurred by Landlord in
repairing or replacing the piping so damaged.

          Tenant agrees to provide Landlord with: (1) a copy of any hazardous
material management plan or similar document required by any federal, state or
local governmental or regulatory authority to be submitted by Tenant; (2) copies
of all permits, licenses and other governmental and regulatory approvals with
respect to the use of Hazardous Material; (3) copies of hazardous waste
manifests reflecting the legal and proper disposal of all Hazardous Material
removed from the Premises; and (4) copies of all reports, studies and written
results of tests or inspections concerning the Premises or any part of the
Project with respect to Hazardous Material, including the "Plans" hereinafter
defined (collectively "Documents"). Tenant shall deliver all Documents to
Landlord promptly following the earlier of (i) Tenant's submission of such
Documents to the requesting governmental agency, or (ii) Tenant's receipt of
such Documents (Tenant hereby agreeing that it shall exercise diligent efforts
to expeditiously obtain copies of any such Documents known by Tenant to exist).

     (c)  Upon commencing any activity involving Hazardous Material on the
Premises, and continuing thereafter throughout the term of this Lease, Tenant
shall initiate and maintain the systems set forth in the following
(collectively, "Plans") in order to ensure the routine monitoring of the levels
of Hazardous Material which may be present on, under or about the Premises or
any part of the Project or properties adjoining or in the vicinity of the
Project as the result of the activities of Tenant or Tenant's Agents and to
ensure continued compliance with the procedures and regulations concerning the
handling, storage, use and disposal of Hazardous Material:  (1) each permit,
license or other governmental or regulatory approval with respect to the use of
Hazardous Material, (2) each Hazardous Material management plan or similar
document required by any federal, state, or local governmental or regulatory
entity, (3) each plan for handling and disposing of Hazardous Material necessary
to comply with Environmental Laws prepared by or on behalf of Tenant or Tenant's
Agents (whether or not required to be submitted to a governmental agency).
Copies of the foregoing described Plans are listed on Exhibit E hereto and
                                                      ---------           
attached to this Lease as Exhibits E-1 through E-____.
                          ------------          

     (d)  Not less often than once each calendar year during the term of this
Lease, Tenant shall provide Landlord with a written report which shall set forth
the results of the monitoring of Hazardous Material during the previous calendar
year. Landlord may elect (but shall not be obligated) to retain an independent
consultant experienced in the use and management of Hazardous Material for the
purpose of reviewing any information received by Landlord in connection with
Hazardous Material. Pursuant to such review, Landlord's consultant may make
recommendations in connection with Tenant's control of Hazardous Material on the
Premises, and Tenant shall implement, at Tenant's sole cost, the recommendations
of Landlord's consultant.  Landlord's failure to appoint any consultant shall
not relieve Tenant of any of Tenant's obligations under this Lease relating to
Hazardous Material nor constitute a waiver of Landlord's rights under this
Lease.  In the event that Landlord's consultant discovers that Tenant's
procedures constitute or will result in a non-deminimis violation of the
provisions of this Section, Tenant shall promptly cure such violation and, as
necessary, modify its procedures, at its sole cost and expense, to the
reasonable satisfaction of Landlord's consultant.

     (e)  Landlord may install permanent or other testing wells or devices at or
about the Premises or any part of the Project, and may cause the ground water to
be tested to detect the presence of Hazardous Material at least once every
twelve (12) months during the term of this Lease by the use of such wells or
devices as are then customarily used for such purposes. If Tenant so requests in
writing, Landlord shall supply Tenant with a copy of any such test results. The
costs of any such tests, and the installation, maintenance, repair, removal,
closure and replacement of such wells or devices shall be included in Operating
Expenses pursuant to this Lease; provided, however, such costs shall be borne
solely by Tenant if 

                                       12
<PAGE>
 
the same are incurred by Landlord based upon Landlord's reasonable belief, at
the time such testing is initiated, that Tenant is in breach of its obligations
under this Section 7.02 or if, following the initiation of such testing, the
presence of Hazardous Material is detected and Tenant or Tenant's Agents are
responsible therefor. Tenant's obligations under this Section 7.02(e)shall
survive the expiration or earlier termination of this Lease.

     (f)  Landlord and its representative shall have the right, at the following
times, to enter the Premises and to: (i) conduct any testing, monitoring and
analysis for Hazardous Material; (ii) review any documents, materials,
inventory, financial data or notices or correspondence to or from private
parties or governmental or regulatory authorities in connection therewith; and
(iii) review all storage, use, transportation and disposal facilities and
procedures associated with the storage, use, transportation and disposal of
Hazardous Material (collectively, "Inspection"):

          (1)  Once every six (6) months for the first twelve (12) months after
the later of the date Tenant introduces Hazardous Material to the Premises
pursuant to this Section 7.02 or notifies Landlord of such use, and once every
twelve (12) months thereafter throughout the term of this Lease. Tenant agrees
to notify Landlord at least five (5) business days prior to the use or storage
in, or transportation to, the Premises of Hazardous Material; and

          (2)  At any time during the term of this Lease if, in Landlord's
reasonable judgment, Tenant is breaching its obligation under this Section 7.02
or is not in compliance with any other provision of this Lease.

          All costs and expenses incurred by Landlord in connection with any
Inspection pursuant to this Section 7.02(f) shall, subject to Section 7.02(n)
below, become due and payable by Tenant as additional Rent, upon presentation by
Landlord of an invoice therefor.

     (g)  Tenant shall give prompt written notice to Landlord of:

          (1)  any proceeding or inquiry by, notice from, or order of any
governmental authority (including the California State Department of Health
Services) with respect to the presence of any Hazardous Material on, under or
about the Premises or any part of the Project or the migration thereof from or
to other property;

          (2)  all claims made or threatened by any third party against Tenant,
the Premises or any part of the Project relating to any loss or injury resulting
from any Hazardous Material; and

          (3)  any spill, release, discharge or nonroutine disposal of Hazardous
Material that occurs with respect to the Premises or operations at the Premises
by Tenant or Tenant's Agents;

          (4)  all matters of which Tenant is required to give notice pursuant
to Sections 25249.5 et seq. and 25359.7 of the California Health and Safety
                    -- ---                                                 
Code; and

          (5)  Tenant's discovery of any occurrence or condition on, under or
about the Premises or any part of the Project or any real property adjoining or
in the vicinity of the Premises or the Project that could cause the Premises or
any part of the Project to be subject to any restrictions on the ownership,
occupancy, transferability or use of the Premises or any part of the Project
under any Environmental Laws, including without limitation, Tenant's discovery
of any occurrence or condition on any real property adjoining or in the vicinity
of the Premises or the Project that could cause the Premises or any part of the
Project to be classified as "border zone property" under the provisions of
California Health and Safety Code Sections 25220 et seq. or any regulation
                                                 -- ---                   
adopted in accordance therewith, or to be otherwise subject to any restrictions
on the ownership, occupancy, transferability or use of the Premises or any part
of the Project under any Environmental Laws.

     (h)  Landlord shall have the right to join and participate in, as a party
if it so elects, any legal proceedings or actions affecting the Premises or any
part of the Project initiated in connection with any Environmental Laws and have
its attorneys' fees in connection therewith paid by Tenant. In addition, Tenant
shall not take any remedial action in response to the presence of any Hazardous
Material in, under, or about the Premises or the Project (except in the case
where loss of life or substantial property damage is imminent or immediate
action is required by any governmental entity, in which event Tenant shall take
immediate remedial action), nor enter into any settlement agreement, consent
decree or other compromise in respect to any claims relating to any Hazardous
Material in any way connected with the Premises or the Project, without first
notifying Landlord of Tenant's intention to do so and affording Landlord ample
opportunity to appear, intervene or otherwise appropriately assert and protect
Landlord's interest with respect thereto.

     (i)  To the extent permitted by law, Tenant hereby indemnifies and agrees
to protect, defend and hold the Indemnitees harmless against any actions,
claims, demands, liability, costs and expenses, including attorneys' fees and
costs, arising from the use, generation, manufacture, production, storage,
release, threatened release, discharge, disposal, transportation to or from, or
presence of any Hazardous Material on, under or about the Premises or any part
of the Project caused by Tenant or by Tenant's Agents (collectively a "Release")
including, without limitation: (1) all foreseeable consequential damages,
including loss of rental income and diminution in property value; (2) the costs
of any investigation, monitoring, removal, restoration, abatement, repair,
cleanup, detoxification or other ameliorative work of any kind or nature

                                       13
<PAGE>
 
(collectively "Remedial Work") and the preparation and implementation of any
closure, remedial or other required plans; (3) any injury to or death of persons
or damage to or destruction of property; and (4) any failure of Tenant or
Tenant's Agents to observe the covenants of this Section 7.02.  For purposes of
this Section 7.02(i), any acts or omissions of Tenant's Agents (whether or not
they are negligent, intentional, willful or unlawful) shall be strictly
attributable to Tenant.  In case of any action of proceeding brought against the
Indemnitees by reason of any such claim, upon notice from Landlord, Tenant
covenants to defend such action or proceeding by counsel chosen by Landlord, in
Landlord's sole discretion.  Landlord reserves the right to settle, compromise
or dispose of any and all actions, claims and demands related to the foregoing
indemnity.  Tenant's obligations under this Section 7.02(i) shall survive the
expiration or earlier termination of this Lease.  The foregoing indemnity shall
not operate to relieve Landlord of any liability Landlord has under
Environmental Laws to the extent Hazardous Materials are present on, under or
about the Premises or the Project prior to delivery to Tenant of possession of
the Premises.

          In no event shall Landlord be responsible to Tenant for the presence
of Hazardous Material in, on or about the Premises or the Project to the extent
caused or contributed to by any third party.

     (j)  Within forty-five (45) days following the end of Tenant's fiscal year,
Tenant shall provide Landlord with financial statements prepared in accordance
with generally accepted accounting principles consistently applied and certified
as true and correct by Tenant's independent certified public accountant setting
forth Tenant's performance for the applicable fiscal year.  So long as Tenant is
not a publically traded company, the preceding sentence shall not apply, but
Tenant shall make available to Landlord, at mutually convenient times, at
Landlord's request, from time to time, financial statements prepared in
accordance with generally accepted accounting principles consistently applied
and certified as true and correct by Tenant's independent certified public
accountant setting forth Tenant's performance for the applicable fiscal year,
for inspection and review by Landlord at the Premises.  As of the execution of
this Lease, Tenant's fiscal year ends December 31.  Tenant shall provide
Landlord with prompt written notice of any change in Tenant's fiscal year. If at
any time it reasonably appears to Landlord that Tenant is not maintaining
sufficient insurance or is not otherwise financially capable of fulfilling its
obligations under this Section 7.02, whether or not such obligations have
accrued, become liquidated, conditional or contingent, Tenant shall procure and
thereafter maintain in full force and effect such insurance or other form of
financial assurance, with or from companies or persons and in forms reasonably
acceptable to Landlord, as Landlord may from time to time request.

     (k)  Upon any Release, Tenant shall, subject to Section 7.02(h), promptly
notify Landlord of the Release and shall, at its sole expense and immediately
after demand by Landlord, commence to perform and thereafter diligently
prosecute to completion such Remedial Work as is necessary to restore the
Premises, Project or any other property affected by the Release to the condition
existing prior to the use of any Hazardous Material by Tenant and/or Tenant's
Agents. All such Remedial Work shall be performed:  (1) in conformance with the
requirements of all applicable Environmental Laws; (2) by one or more
contractors, approved in advance in writing by Landlord; and (3) under the
supervision of a consulting engineer approved in advance in writing by Landlord.
All costs and expenses of such Remedial Work shall be paid by Tenant including
the charges of such contractor(s) and/or the consulting engineer and Landlord's
reasonable attorneys' fees and costs incurred in connection with the monitoring
or review of such Remedial Work. In the event Tenant shall fail to timely
commence, or cause to be commenced, or fail to diligently prosecute to
completion, such Remedial Work, Landlord may, but shall not be required to,
cause such Remedial Work to be performed and all costs and expenses thereof, or
incurred in connection therewith, shall become immediately due and payable by
Tenant.  Tenant's obligations under this Section 7.02(k) shall survive the
expiration or sooner termination of this Lease.

     (l)  Hazardous Material shall include by way of illustration, and without
limiting the generality of the definition of Hazardous Material in Section 1.03,
the following:  (i) those substances included within the definitions of
"hazardous substances," "hazardous materials," "toxic substances" or "solid
waste" under all present and future federal, state and local laws (whether under
common law, statute, rule, regulation or otherwise) relating to the protection
of human health or the environment, including California Senate Bill 245
(Statutes of 1987, Chapter 1302), the Safe Drinking Water and Toxic Enforcement
Act of 1986 (commonly known as Proposition 65) and the Comprehensive
Environmental Response, Compensation and Liability Act of 1980, as amended, 42
U.S.C. Section 9601 et seq., the Resource Conservation and Recovery Act of 1976,
                    -- ---                                                      
42 U.S.C. Section 6901 et seq., and the Hazardous Materials Transportation Act,
                       -- ---                                                  
49 U.S.C. Sections 1801, et seq., all as heretofore and hereafter amended, or in
                         -- ---                                                 
any regulations promulgated pursuant to said laws; (ii) those substances defined
as "hazardous wastes" in Section 25117 of the California Health & Safety Code or
as "hazardous substances" in Section 25316 of the California Health & Safety
Code, or in any regulations promulgated pursuant to said laws; (iii) those
substances listed in the United States Department of Transportation Table (49
CFR 172.101 and amendments thereto) or designated by the Environmental
Protection Agency (or any successor agency) as hazardous substances (see, e.g.,
                                                                     ---  ---- 
40 CFR Part 302 and amendments thereto); (iv) such other substances, materials
and wastes which are or become regulated under applicable local, state or
federal law or by the United States government or which are or become classified
as hazardous or toxic under federal, state or local laws or regulations,
including California Health & Safety Code, Division 20, and Title 26 of the
California Code of Regulations; and (v) any material, waste or substance which
contains petroleum, asbestos or polychlorinated biphenyls, is designated as a
"hazardous substance" pursuant to Section 311 of the Clean Water Act of 1977, 33
U.S.C. Sections 1251, et seq. (33 U.S.C. (S) 1321), is listed pursuant to
                      ------                                             
Section 307 of the Clean Water Act of 1977 (33 U.S.C. (S) 1317), or contains any
flammable, explosive or radioactive material.

                                       14
<PAGE>
 
     (m) In addition to Tenant's obligations pursuant to Article Twelve of this
Lease, Tenant shall, on the expiration or sooner termination of this Lease,
surrender the Premises to Landlord free of Hazardous Material for which Tenant
is responsible hereunder. If Tenant fails to so surrender the Premises and the
Project, the provisions of Section 7.02(i) shall apply.  Landlord shall have the
right, but not the obligation, to appoint a consultant, at Tenant's expense, to
conduct an investigation to determine whether any Hazardous Material are located
in or about the Premises or the Project, and to determine the corrective
measures required to remove such Hazardous Material. Tenant, at its expense,
shall comply with all recommendations of the consultant. A failure by Landlord
to appoint such a consultant shall in no way relieve Tenant of any of Tenant's
obligations set forth in this Lease relating to Hazardous Material, nor
constitute a waiver of Landlord's rights under this Lease.  Tenant's obligations
under this Section 7.02(m) shall survive the expiration or earlier termination
of this Lease.

     (n) Except as otherwise provided in Section 7.02(d) (concerning the
implementation of consultant recommendations) and Section 7.02(k) (concerning
the monitoring and review of Remedial Work), all costs incurred by Landlord in
retaining a consultant for any purpose contained in this Section 7.02 shall be
included in Operating Expenses under this Lease unless Landlord retains a
consultant pursuant to this Section 7.02, and such consultant reasonably
determines after appropriate review of information and/or inspection that Tenant
is breaching its obligations under this Lease to comply with this Section 7.02,
in which event all costs and expenses incurred by Landlord in connection with
any such review, inspection, and/or implementation of recommendations pursuant
to this Section 7.02 shall become due and payable by Tenant as additional Rent,
upon presentation by Landlord of an invoice therefor.

     (o) Upon any violation of any of the foregoing covenants, Landlord shall be
entitled to exercise all remedies available to a landlord against a defaulting
tenant, including but not limited to those set forth in Article Eleven of this
Lease.  No action by Landlord hereunder shall impair the obligations of Tenant
pursuant to Section 7.02.

7.03 LANDLORD ACCESS TO PREMISES; APPROVALS

     (a) Tenant shall permit Landlord to erect, use and maintain pipes, ducts,
wiring and conduits in and through the Premises, so long as Tenant's use, layout
or design of the Premises is not materially affected or altered.  Landlord or
Landlord's agents shall have the right to enter upon the Premises in the event
of an emergency, or, upon twenty-four (24) hours prior notice to Tenant, to
inspect the Premises, to perform janitorial and other services (if any), to
conduct safety and other testing in the Premises and to make such repairs,
alterations, improvements or additions to the Premises or the Building or other
parts of the Property as Landlord may deem necessary or desirable (including all
alterations, improvements and additions in connection with a change in service
provider or providers).  Janitorial and cleaning services (if any) shall be
performed after normal business hours.  Any entry or work by Landlord may be
during normal business hours and Landlord may use reasonable efforts to ensure
that any entry or work shall not materially interfere with Tenant's occupancy of
the Premises.

     (b) If Tenant shall not be personally present to permit an entry into the
Premises when for any reason an entry therein shall be necessary or permissible,
Landlord (or Landlord's agents), after attempting to notify Tenant (unless
Landlord believes an emergency situation exists), may enter the Premises without
rendering Landlord or its agents liable therefor, and without relieving Tenant
of any obligations under this Lease.

     (c) Upon twenty-four (24) hours notice to Tenant (or such shorter notice as
may be reasonable in an emergency), Landlord may enter the Premises for the
purpose of conducting such inspections, tests and studies as Landlord may deem
desirable or necessary to confirm Tenant's compliance with all Laws and
Environmental Laws or for other purposes necessary in Landlord's reasonable
judgment to ensure the sound condition of the Property and the systems serving
the Property.  Landlord's rights under this Section 7.02(c) are for Landlord's
own protection only, and Landlord has not, and shall not be deemed to have
assumed, any responsibility to Tenant or any other party as a result of the
exercise or non-exercise of such rights, for compliance with Laws or
Environmental Laws or for the accuracy or sufficiency of any item or the quality
or suitability of any item for its intended use.

     (d) Landlord may do any of the foregoing, or undertake any of the
inspection or work described in the preceding paragraphs without such action
constituting an actual or constructive eviction of Tenant, in whole or in part,
or giving rise to an abatement of Rent by reason of loss or interruption of
business of the Tenant, or otherwise.

     (e) The review, approval or consent of Landlord with respect to any item
required or permitted under this Lease is for Landlord's own protection only,
and Landlord has not, and shall not be deemed to have assumed, any
responsibility to Tenant or any other party, as a result of the exercise or non-
exercise of such rights, for compliance with Laws or Environmental Laws or for
the accuracy or sufficiency of any item or the quality or suitability of any
item for its intended use.

7.04 QUIET ENJOYMENT

Landlord covenants, in lieu of any implied covenant of quiet possession or quiet
enjoyment, that so long as Tenant is in compliance with the covenants and
conditions set forth in this Lease, Tenant shall have the right

                                       15
<PAGE>
 
to quiet enjoyment of the Premises without hindrance or interference from
Landlord or those claiming through Landlord, and subject to the covenants and
conditions set forth in the Lease and to the rights of any Mortgagee or ground
lessor.

                                 ARTICLE EIGHT
                                  MAINTENANCE

8.01 LANDLORD'S MAINTENANCE

Subject to Article Fourteen and Section 8.02, Landlord shall maintain the
structural portions of the Building, the roof, exterior walls and exterior
doors, foundation, and underslab standard sewer system of the Building in good,
clean and safe condition, and shall use reasonable efforts, through Landlord's
program of regularly scheduled preventive maintenance, to keep the Building's
standard heating, ventilation and air conditioning ("HVAC") equipment in
reasonably good order and condition.  Notwithstanding the foregoing, Landlord
shall have no responsibility to repair the Building's standard heating,
ventilation and air conditioning equipment, and all such repairs shall be
performed by Tenant pursuant to the terms of Section 8.02.  Landlord shall also
(a) maintain the landscaping, parking facilities and other Common Areas of the
Project, and (b) wash the outside of exterior windows at intervals reasonably
determined by Landlord.  Except as provided in Article Fourteen and Article
Fifteen, there shall be no abatement of rent, no allowance to Tenant for
diminution of rental value and no liability of Landlord by reason of
inconvenience, annoyance or any injury to or interference with Tenant's business
arising from the making of or the failure to make any repairs, alterations or
improvements in or to any portion of the Project or in or to any fixtures,
appurtenances or equipment therein.  Tenant waives the right to make repairs at
Landlord's expense under any law, statute or ordinance now or hereafter in
effect.

8.02 TENANT'S MAINTENANCE

Subject to the provisions of Article Fourteen, Tenant shall, at Tenant's sole
cost and expense, make all repairs to the Premises and fixtures therein which
Landlord is not required to make pursuant to Section 8.01, including repairs to
the interior walls, ceilings and windows of the Premises, the interior doors,
Tenant's signage, and the electrical, life-safety, plumbing and heating,
ventilation and air conditioning systems located within or serving the Premises
and shall maintain the Premises, the fixtures and utilities systems therein, and
the area immediately surrounding the Premises (including all garbage
enclosures), in a good, clean and safe condition.  Tenant shall deliver to
Landlord a copy of any maintenance contract entered into by Tenant with respect
to the Premises.  Tenant shall also, at Tenant's expense, keep any non-standard
heating, ventilating and air conditioning equipment and other non-standard
equipment in the Building in good condition and repair, using contractors
approved in advance, in writing, by Landlord.  Notwithstanding Section 8.01
above, but subject to the waivers set forth in Section 16.04, Tenant will pay
for any repairs to the Building or the Project which are caused by any
negligence or carelessness, or by any willful and wrongful act, of Tenant or its
assignees, subtenants or employees, or of the respective agents of any of the
foregoing persons, or of any other persons permitted in the Building or
elsewhere in the Project by Tenant or any of them.  Tenant will maintain the
Premises, and will leave the Premises upon termination of this Lease, in a safe,
clean, neat and sanitary condition.

                                 ARTICLE NINE
                         ALTERATIONS AND IMPROVEMENTS

9.01 TENANT ALTERATIONS

     (a)  The following provisions shall apply to the completion of any Tenant
Alterations:

          (1) Tenant shall not, except as provided herein, without the prior
     written consent of Landlord, which consent shall not be unreasonably
     withheld, make or cause to be made any Tenant Alterations in or to the
     Premises or any Property systems serving the Premises.  Prior to making any
     Tenant Alterations, Tenant shall give Landlord ten (10) days prior written
     notice (or such earlier notice as would be necessary pursuant to applicable
     Law) to permit Landlord sufficient time to post appropriate notices of non-
     responsibility. Subject to all other requirements of this Article Nine,
     Tenant may undertake Decoration work without Landlord's prior written
     consent.  Tenant shall furnish Landlord with the names and addresses of all
     contractors and subcontractors and copies of all contracts.  All Tenant
     Alterations shall be completed at such time and in such manner as Landlord
     may from time to time designate, and only by contractors or mechanics
     approved by Landlord, which approval shall not be unreasonably withheld,
     provided, however, that Landlord may, in its sole discretion, specify the
     engineers and contractors to perform all work relating to the Building's
     systems (including the mechanical, heating, plumbing, security,
     ventilating, air-conditioning, electrical, communication and the fire and
     life safety systems in the Building).  The contractors, mechanics and
     engineers who may be used are further limited to those whose work will not
     cause or threaten to cause disharmony or interference with Landlord or
     other tenants in the Building and their respective agents and contractors
     performing work in or about the Building.  Landlord may further condition
     its consent upon Tenant furnishing to Landlord and Landlord approving prior
     to the commencement of any work or delivery of materials to the Premises
     related to the Tenant Alterations such of the following as specified by
     Landlord:  architectural plans and specifications, opinions from Landlord's
     engineers stating that the Tenant Alterations will not in any way adversely
     affect the

                                       16
<PAGE>
 
     Building's systems, necessary permits and licenses, certificates of
     insurance, and such other documents in such form reasonably requested by
     Landlord. Upon completion of the Tenant Alterations, Tenant shall deliver
     to Landlord two (2) sets of as-built mylar and digitized plans and
     specifications for the Tenant Alterations.

          (2) Tenant shall pay the cost of all Tenant Alterations and the cost
     of decorating the Premises and any work to the Property occasioned thereby.
     In connection with completion of any Tenant Alterations, Tenant shall pay
     Landlord hoisting charges at Landlord's then standard rate.  Upon
     completion of Tenant Alterations, Tenant shall furnish Landlord with
     contractors' affidavits and full and final waivers of lien and receipted
     bills covering all labor and materials expended and used in connection
     therewith and such other documentation reasonably requested by Landlord or
     Mortgagee.

          (3) Tenant agrees to complete all Tenant Alterations (i) in accordance
     with all Laws, Environmental Laws, all requirements of applicable insurance
     companies and in accordance with Landlord's standard construction rules and
     regulations, and (ii) in a good and workmanlike manner with the use of good
     grades of materials.  Tenant shall notify Landlord immediately if Tenant
     receives any notice of violation of any Law in connection with completion
     of any Tenant Alterations and shall immediately take such steps as are
     necessary to remedy such violation.  In no event shall such supervision or
     right to supervise by Landlord nor shall any approvals given by Landlord
     under this Lease constitute any warranty by Landlord to Tenant of the
     adequacy of the design, workmanship or quality of such work or materials
     for Tenant's intended use or of compliance with the requirements of Section
     9.01(a)(3)(i) and (ii) above or impose any liability upon Landlord in
     connection with the performance of such work.

     (b)  All Tenant Additions to the Premises whether installed by Landlord or
Tenant, shall without compensation or credit to Tenant, become part of the
Premises and the property of Landlord at the time of their installation and
shall remain in the Premises, unless pursuant to Article Twelve, Tenant may
remove them or is required to remove them at Landlord's request.

9.02 LIENS

Tenant shall not permit any lien or claim for lien of any mechanic, laborer or
supplier or any other lien to be filed against the Building, the Land, the
Premises, or any other part of the Property arising out of work performed, or
alleged to have been performed by, or at the direction of, or on behalf of
Tenant.  If any such lien or claim for lien is filed, Tenant shall within ten
(10) days of receiving notice of such lien or claim (a) have such lien or claim
for lien released of record or (b) deliver to Landlord  a bond in form, content,
amount, and issued by surety, satisfactory to Landlord, indemnifying,
protecting, defending and holding harmless the Indemnitees against all costs and
liabilities resulting from such lien or claim for lien and the foreclosure or
attempted foreclosure thereof.  If Tenant fails to take any of the above
actions, Landlord, in addition to its rights and remedies under Article Eleven,
without investigating the validity of such lien or claim for lien, may pay or
discharge the same and Tenant shall, as payment of additional Rent hereunder,
reimburse Landlord upon demand for the amount so paid by Landlord, including
Landlord's expenses and attorneys' fees.

                                  ARTICLE TEN
                           ASSIGNMENT AND SUBLETTING

10.01 ASSIGNMENT AND SUBLETTING

      (a) Without the prior written consent of Landlord, which may be withheld
in Landlord's sole discretion, Tenant may not sublease, assign, mortgage,
pledge, hypothecate or otherwise transfer or permit the transfer of this Lease
or the encumbering of Tenant's interest therein in whole or in part, by
operation of Law or otherwise or permit the use or occupancy of the Premises, or
any part thereof, by anyone other than Tenant, provided, however, if Landlord
chooses not to recapture the space proposed to be subleased or assigned as
provided in Section 10.02, Landlord shall not unreasonably withhold its consent
to a subletting or assignment under this Section 10.01. Tenant agrees that the
provisions governing sublease and assignment set forth in this Article Ten shall
be deemed to be reasonable. If Tenant desires to enter into any sublease of the
Premises or assignment of this Lease, Tenant shall deliver written notice
thereof to Landlord ("Tenant's Notice"), together with the identity of the
proposed subtenant or assignee and the proposed principal terms thereof and
financial and other information sufficient for Landlord to make an informed
judgment with respect to such proposed subtenant or assignee at least thirty
(30) days prior to the commencement date of the term of the proposed sublease or
assignment. If Tenant proposes to sublease less than all of the Rentable Area of
the Premises, the space proposed to be sublet and the space retained by Tenant
must each be a marketable unit as reasonably determined by Landlord and
otherwise in compliance with all Laws. Landlord shall notify Tenant in writing
of its approval or disapproval of the proposed sublease or assignment or its
decision to exercise its rights under Section 10.02 within fifteen (15) days
after receipt of Tenant's Notice (and all required information). In no event may
Tenant sublease any portion of the Premises or assign the Lease to any other
tenant of the Project. Tenant shall submit for Landlord's approval (which
approval shall not be unreasonably withheld) any advertising which Tenant or its
agents intend to use with respect to the space proposed to be sublet.

                                       17
<PAGE>
 
     (b) With respect to Landlord's consent to an assignment or sublease,
Landlord may take into consideration any factors which Landlord may deem
relevant, and the reasons for which Landlord's denial shall be deemed to be
reasonable shall include, without limitation, the following:

     (i) the business reputation or creditworthiness of any proposed subtenant
     or assignee is not acceptable to Landlord; or

     (ii) in Landlord's reasonable judgment the proposed assignee or subtenant
     would diminish the value or reputation of the Building or Landlord; or

     (iii)  any proposed assignee's or subtenant's use of the Premises would
     violate Section 7.01 of the Lease or would violate the provisions of any
     other leases of tenants in the Project;

     (iv) the proposed assignee or subtenant is either a governmental agency, a
     school or similar operation, or a medical related practice; or

     (v) the proposed subtenant or assignee is a bona fide prospective tenant of
     Landlord in the Project as demonstrated by a written proposal dated within
     ninety (90) days prior to the date of Tenant's request; or

     (vi) the proposed subtenant or assignee would materially increase the
     estimated pedestrian and vehicular traffic to and from the Premises and the
     Building.

In no event shall Landlord be obligated to consider a consent to any proposed
assignment of the Lease which would assign less than the entire Premises.  In
the event Landlord wrongfully withholds its consent to any proposed sublease of
the Premises or assignment of the Lease, Tenant's sole and exclusive remedy
therefor shall be to seek specific performance of Landlord's obligations to
consent to such sublease or assignment.

     (c) Any sublease or assignment shall be expressly subject to the terms and
conditions of this Lease.  Any subtenant or assignee shall execute such
documents as Landlord may reasonably require to evidence such subtenant or
assignee's assumption of the obligations and liabilities of Tenant under this
Lease.  Tenant shall deliver to Landlord a copy of all agreements executed by
Tenant and the proposed subtenant and assignee with respect to the Premises.
Landlord's approval of a sublease, assignment, hypothecation, transfer or third
party use or occupancy shall not constitute a waiver of Tenant's obligation to
obtain Landlord's consent to further assignments or subleases, hypothecations,
transfers or third party use or occupancy.

     (d) For purposes of this Article Ten, an assignment shall be deemed to
include a change in the majority control of Tenant, resulting from any transfer,
sale or assignment of shares of stock of Tenant occurring by operation of Law or
otherwise if Tenant is a corporation whose shares of stock are not traded
publicly.  If Tenant is a partnership, any change in the partners of Tenant
shall be deemed to be an assignment.

10.02 RECAPTURE

Landlord shall have the option to exclude from the Premises covered by this
Lease ("recapture"), the space proposed to be sublet or subject to the
assignment, effective as of the proposed commencement date of such sublease or
assignment.  If Landlord elects to recapture, Tenant shall surrender possession
of the space proposed to be subleased or subject to the assignment to Landlord
on the effective date of recapture of such space from the Premises, such date
being the Termination Date for such space.  Effective as of the date of
recapture of any portion of the Premises pursuant to this section, the Monthly
Base Rent, Rentable Area of the Premises and Tenant's Share shall be adjusted
accordingly.

10.03 EXCESS RENT

Tenant shall pay Landlord on the first day of each month during the term of the
sublease or assignment, one hundred percent (100%) of the amount by which the
sum of all rent and other consideration (direct or indirect) due from the
subtenant or assignee for such month exceeds: (i) that portion of the Monthly
Base Rent and Rent Adjustments due under this Lease for said month which is
allocable to the space sublet or assigned; and (ii) the following costs and
expenses for the subletting or assignment of such space: (1) brokerage
commissions and attorneys' fees and expenses, (2) the actual costs paid in
making any improvements or substitutions in the Premises required by any
sublease or assignment; and (3) "free rent" periods, costs of any inducements or
concessions given to subtenant or assignee, moving costs, and other amounts in
respect of such subtenant's or assignee's other leases or occupancy
arrangements.  All such costs and expenses shall be amortized over the term of
the sublease or assignment pursuant to sound accounting principles.

10.04 TENANT LIABILITY

In the event of any sublease or assignment, whether or not with Landlord's
consent, Tenant shall not be released or discharged from any liability, whether
past, present or future, under this Lease, including any 

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<PAGE>
 
liability arising from the exercise of any renewal or expansion option, to the
extent such exercise is expressly permitted by Landlord. Tenant's liability
shall remain primary, and in the event of default by any subtenant, assignee or
successor of Tenant in performance or observance of any of the covenants or
conditions of this Lease, Landlord may proceed directly against Tenant without
the necessity of exhausting remedies against said subtenant, assignee or
successor. After any assignment, Landlord may consent to subsequent assignments
or subletting of this Lease, or amendments or modifications of this Lease with
assignees of Tenant, without notifying Tenant, or any successor of Tenant, and
without obtaining its or their consent thereto, and such action shall not
relieve Tenant or any successor of Tenant of liability under this Lease. If
Landlord grants consent to such sublease or assignment, Tenant shall pay all
reasonable attorneys' fees and expenses incurred by Landlord with respect to
such assignment or sublease. In addition, if Tenant has any options to extend
the term of this Lease or to add other space to the Premises, such options shall
not be available to any subtenant or assignee, directly or indirectly without
Landlord's express written consent, which may be withheld in Landlord's sole
discretion.

10.05 ASSUMPTION AND ATTORNMENT

If Tenant shall assign this Lease as permitted herein, the assignee shall
expressly assume all of the obligations of Tenant hereunder in a written
instrument satisfactory to Landlord and furnished to Landlord not later than
fifteen (15) days prior to the effective date of the assignment.  If Tenant
shall sublease the Premises as permitted herein, Tenant shall, at Landlord's
option, within fifteen (15) days following any request by Landlord, obtain and
furnish to Landlord the written agreement of such subtenant to the effect that
the subtenant will attorn to Landlord and will pay all subrent directly to
Landlord.

10.06 TRANSFER TO TENANT AFFILIATE

Anything in this Section to the contrary notwithstanding, Tenant may assign this
Lease or sublet all or a portion of the Premises to any entity which controls,
is controlled by or is under common control with Maxygen, Inc. (each a "Tenant
Affiliate"), without the prior consent of Landlord, and Landlord shall have no
right to recapture the Premises subject to such sublease or assignment;
provided, however, that in order for any such assignment or sublease to be
effective, Landlord shall be given prior written notice of same and any such
assignment or sublease shall comply with the requirements set forth in Section
10.05, and shall be in effect only so long as such entity controls, is
controlled by or is under common control with Maxygen, Inc.  In addition, no
such assignment or sublease shall relieve Tenant of any obligation to be
performed by Tenant under this Lease, whether occurring before or after any such
assignment or sublease.  For purposes of this Section, the term "control" means
(i) the beneficial ownership, directly or indirectly, of not less than fifty-one
percent (51%) of the voting common stock or equity interests of the controlled
entity and (ii) the controlling entity manages, directly or indirectly, the
controlled entity.

                                ARTICLE ELEVEN
                             DEFAULT AND REMEDIES

11.01 EVENTS OF DEFAULT

The occurrence or existence of any one or more of the following shall constitute
a "Default" by Tenant under this Lease:

          (i)  Tenant fails to pay any installment or other payment of Rent
     including Rent Adjustment Deposits or Rent Adjustments within three (3)
     days after the date when due;

          (ii)  Tenant fails to observe or perform any of the other covenants,
     conditions or provisions of this Lease or the Workletter and fails to cure
     such default within fifteen (15) days after written notice thereof to
     Tenant, unless the default involves a hazardous condition, which shall be
     cured forthwith or unless the failure to perform is a Default for which
     this Lease specifies there is no cure or grace period;

          (iii)  the interest of Tenant in this Lease is levied upon under
     execution or other legal process;

          (iv)  a petition is filed by or against Tenant to declare Tenant
     bankrupt or seeking a plan of reorganization or arrangement under any
     Chapter of the Bankruptcy Act, or any amendment, replacement or
     substitution therefor, or to delay payment of, reduce or modify Tenant's
     debts, which in the case of an involuntary action is not discharged within
     thirty (30) days;

          (v)  Tenant is declared insolvent by Law or any assignment of Tenant's
     property is made for the benefit of creditors;

          (vi)  a receiver is appointed for Tenant or Tenant's property, which
     appointment is not discharged within thirty (30) days;

          (vii)  any action taken by or against Tenant to reorganize or modify
     Tenant's capital structure in a materially adverse way which in the case of
     an involuntary action is not discharged within thirty (30) days;

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<PAGE>
 
          (viii)  upon the dissolution of Tenant; or

          (ix)  upon the third occurrence within any Lease Year that Tenant
     fails to pay Rent when due or has breached a particular covenant of this
     Lease (whether or not such failure or breach is thereafter cured within any
     stated cure or grace period or statutory period).

11.02 LANDLORD'S REMEDIES

     (a) A Default shall constitute a breach of the Lease for which Landlord
shall have the rights and remedies set forth in this Section 11.02 and all other
rights and remedies set forth in this Lease or now or hereafter allowed by Law,
whether legal or equitable, and all rights and remedies of Landlord shall be
cumulative and none shall exclude any other right or remedy.

     (b) With respect to a Default, at any time Landlord may terminate Tenant's
right to possession by written notice to Tenant stating such election.  Any
written notice required pursuant to Section 11.01 shall constitute notice of
unlawful detainer pursuant to California Code of Civil Procedure Section 1161
if, at Landlord's sole discretion, it states Landlord's election that Tenant's
right to possession is terminated after expiration of any period required by Law
or any longer period required by Section 11.01.  Upon the expiration of the
period stated in Landlord's written notice of termination (and unless such
notice provides an option to cure within such period and Tenant cures the
Default within such period), Tenant's right to possession shall terminate and
this Lease shall terminate, and Tenant shall remain liable as hereinafter
provided.  Upon such termination in writing of Tenant's right to possession,
Landlord shall have the right, subject to applicable Law, to re-enter the
Premises and dispossess Tenant and the legal representatives of Tenant and all
other occupants of the Premises by unlawful detainer or other summary
proceedings, or otherwise as permitted by Law, regain possession of the Premises
and remove their property (including their trade fixtures, personal property and
those Tenant Additions which Tenant is required or permitted to remove under
Article Twelve), but Landlord shall not be obligated to effect such removal, and
such property may, at Landlord's option, be stored elsewhere, sold or otherwise
dealt with as permitted by Law, at the risk of, expense of and for the account
of Tenant, and the proceeds of any sale shall be applied pursuant to Law.
Landlord shall in no event be responsible for the value, preservation or
safekeeping of any such property.  Tenant hereby waives all claims for damages
that may be caused by Landlord's removing or storing Tenant's personal property
pursuant to this Section or Section 12.01, and Tenant hereby indemnifies, and
agrees to defend, protect and hold harmless, the Indemnitees from any and all
loss, claims, demands, actions, expenses, liability and cost (including
attorneys' fees and expenses) arising out of or in any way related to such
removal or storage.  Upon such written termination of Tenant's right to
possession and this Lease, Landlord shall have the right to recover damages for
Tenant's Default as provided herein or by Law, including the following damages
provided by California Civil Code Section 1951.2:

          (1) the worth at the time of award of the unpaid Rent which had been
     earned at the time of termination;

          (2) the worth at the time of award of the amount by which the unpaid
     Rent which would have been earned after termination until the time of award
     exceeds the amount of such Rent loss that Tenant proves could reasonably
     have been avoided;

          (3) the worth at the time of award of the amount by which the unpaid
     Rent for the balance of the term of this Lease after the time of award
     exceeds the amount of such Rent loss that Tenant proves could be reasonably
     avoided; and

          (4) any other amount necessary to compensate Landlord for all the
     detriment proximately caused by Tenant's failure to perform its obligations
     under this Lease or which in the ordinary course of things would be likely
     to result therefrom.  The word "rent" as used in this Section 11.02 shall
     have the same meaning as the defined term Rent in this Lease.  The "worth
     at the time of award" of the amount referred to in clauses (1) and (2)
     above is computed by allowing interest at the Default Rate.  The worth at
     the time of award of the amount referred to in clause (3) above is computed
     by discounting such amount at the discount rate of the Federal Reserve Bank
     of San Francisco at the time of award plus one percent (1%).  For the
     purpose of determining unpaid Rent under clause (3) above, the monthly Rent
     reserved in this Lease shall be deemed to be the sum of the Monthly Base
     Rent, and monthly Storage Space Rent, if any, and the amounts last payable
     by Tenant as Rent Adjustments for the calendar year in which Landlord
     terminated this Lease as provided hereinabove.

     (c) Even if Tenant is in Default and/or has abandoned the Premises, this
Lease shall continue in effect for so long as Landlord does not terminate
Tenant's right to possession by written notice as provided in Section 11.02(b)
above, and Landlord may enforce all its rights and remedies under this Lease,
including the right to recover Rent as it becomes due under this Lease.  In such
event, Landlord shall have all of the rights and remedies of a landlord under
California Civil Code Section 1951.4 (lessor may continue Lease in effect after
Tenant's Default and abandonment and recover Rent as it becomes due, if Tenant
has the right to sublet or assign, subject only to reasonable limitations), or
any successor statute.  During such time as Tenant is in Default, if Landlord
has not terminated this Lease by written notice and if Tenant requests
Landlord's consent to an assignment of this Lease or a sublease of the Premises,
subject to Landlord's option to recapture pursuant to Section 10.02, Landlord
shall not unreasonably withhold its consent to such

                                       20
<PAGE>
 
assignment or sublease. Tenant acknowledges and agrees that the provisions of
Article Ten shall be deemed to constitute reasonable limitations of Tenant's
right to assign or sublet. Tenant acknowledges and agrees that in the absence of
written notice pursuant to Section 11.02(b) above terminating Tenant's right to
possession, no other act of Landlord shall constitute a termination of Tenant's
right to possession or an acceptance of Tenant's surrender of the Premises,
including acts of maintenance or preservation or efforts to relet the Premises
or the appointment of a receiver upon initiative of Landlord to protect
Landlord's interest under this Lease or the withholding of consent to a
subletting or assignment, or terminating a subletting or assignment, if in
accordance with other provisions of this Lease.

     (d) In the event that Landlord seeks an injunction with respect to a breach
or threatened breach by Tenant of any of the covenants, conditions or provisions
of this Lease, Tenant agrees to pay the premium for any bond required in
connection with such injunction.

     (e) Tenant hereby waives any and all rights to relief from forfeiture,
redemption or reinstatement granted by Law (including California Civil Code of
Procedure Sections 1174 and 1179) in the event of Tenant being evicted or
dispossessed for any cause or in the event of Landlord obtaining possession of
the Premises by reason of Tenant's Default or otherwise;

     (f) Notwithstanding any other provision of this Lease, a notice to Tenant
given under this Article and Article Twenty-four of this Lease or given pursuant
to California Code of Civil Procedure Section 1161, and any notice served by
mail shall be deemed served, and the requisite waiting period deemed to begin
under said Code of Civil Procedure Section upon mailing, without any additional
waiting requirement under Code of Civil Procedure Section 1011 et seq. or by
other Law.  For purposes of Code of Civil Procedure Section 1162, Tenant's
"place of residence", "usual place of business", "the property" and "the place
where the property is situated" shall mean and be the Premises, whether or not
Tenant has vacated same at the time of service.

     (g) The voluntary or other surrender or termination of this Lease, or a
mutual termination or cancellation thereof, shall not work a merger and shall
terminate all or any existing assignments, subleases, subtenancies or
occupancies permitted by Tenant, except if and as otherwise specified in writing
by Landlord.

     (h) No delay or omission in the exercise of any right or remedy of Landlord
upon any default by Tenant, and no exercise by Landlord of its rights pursuant
to Section 26.15 to perform any duty which Tenant fails timely to perform, shall
impair any right or remedy or be construed as a waiver.  No provision of this
Lease shall be deemed waived by Landlord unless such waiver is in a writing
signed by Landlord.  The waiver by Landlord of any breach of any provision of
this Lease shall not be deemed a waiver of any subsequent breach of the same or
any other provision of this Lease.

11.03 ATTORNEY'S FEES

In the event any party brings any suit or other proceeding with respect to the
subject matter or enforcement of this Lease, the prevailing party (as determined
by the court, agency or other authority before which such suit or proceeding is
commenced) shall, in addition to such other relief as may be awarded, be
entitled to recover attorneys' fees, expenses and costs of investigation as
actually incurred, including court costs, expert witness fees, costs and
expenses of investigation, and all attorneys' fees, costs and expenses in any
such suit or proceeding (including in any action or participation in or in
connection with any case or proceeding under the Bankruptcy Code, 11 United
States Code Sections 101 et seq., or any successor statutes, in establishing or
                         ------                                                
enforcing the right to indemnification, in appellate proceedings, or in
connection with the enforcement or collection of any judgment obtained in any
such suit or proceeding).

11.04 BANKRUPTCY

The following provisions shall apply in the event of the bankruptcy or
insolvency of Tenant:

     (a) In connection with any proceeding under Chapter 7 of the Bankruptcy
Code where the trustee of Tenant elects to assume this Lease for the purposes of
assigning it, such election or assignment, may only be made upon compliance with
the provisions of (b) and (c) below, which conditions Landlord and Tenant
acknowledge to be commercially reasonable.  In the event the trustee elects to
reject this Lease then Landlord shall immediately be entitled to possession of
the Premises without further obligation to Tenant or the trustee.

     (b) Any election to assume this Lease under Chapter 11 or 13 of the
Bankruptcy Code by Tenant as debtor-in-possession or by Tenant's trustee (the
"Electing Party") must provide for:

     The Electing Party to cure or provide to Landlord adequate assurance that
     it will cure all monetary defaults under this Lease within fifteen (15)
     days from the date of assumption and it will cure all nonmonetary defaults
     under this Lease within thirty (30) days from the date of assumption.
     Landlord and Tenant acknowledge such condition to be commercially
     reasonable.

     (c) If the Electing Party has assumed this Lease or elects to assign
Tenant's interest under this Lease to any other person, such interest may be
assigned only if the intended assignee has provided

                                       21
<PAGE>
 
adequate assurance of future performance (as herein defined), of all of the
obligations imposed on Tenant under this Lease.

     For the purposes hereof, "adequate assurance of future performance" means
     that Landlord has ascertained that each of the following conditions has
     been satisfied:

          (i)  The assignee has submitted a current financial statement,
     certified by its chief financial officer, which shows a net worth and
     working capital in amounts sufficient to assure the future performance by
     the assignee of Tenant's obligations under this Lease; and

          (ii)  Landlord has obtained consents or waivers from any third parties
     which may be required under a lease, mortgage, financing arrangement, or
     other agreement by which Landlord is bound, to enable Landlord to permit
     such assignment.

     (d) Landlord's acceptance of rent or any other payment from any trustee,
receiver, assignee, person, or other entity will not be deemed to have waived,
or waive, the requirement of Landlord's consent, Landlord's right to terminate
this Lease for any transfer of Tenant's interest under this Lease without such
consent, or Landlord's claim for any amount of Rent due from Tenant.

11.05 LANDLORD'S DEFAULT

Landlord shall be in default hereunder in the event Landlord has not begun and
pursued with reasonable diligence the cure of any failure of Landlord to meet
its obligations hereunder within thirty (30) days after the receipt by Landlord
of written notice from Tenant of the alleged failure to perform. In no event
shall Tenant have the r