<PAGE>

                                                                   EXHIBIT 10.27

                                 LEASE AGREEMENT

                                   - Between -

                          CURAGEN CORPORATION (Tenant)

                                     - And -

                 16 COMMERCIAL STREET ASSOCIATES, LLC (Landlord)




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                               TABLE OF CONTENTS

                                                                       PAGE NO.

PREMISES......................................................................1
TERM AND USE..................................................................1
RENT..........................................................................1
TENANT'S REPAIRS..............................................................2
LANDLORD'S REPAIRS............................................................2
INSURANCE.....................................................................3
ALTERATIONS AND IMPROVEMENTS..................................................4
ENVIRONMENTAL COMPLIANCE AND INDEMNIFICATIONS.................................4
TENANT'S PROPERTY.............................................................5
UTILITIES AND FUEL............................................................5
ASSIGNMENT AND SUBLETTING.....................................................5
DAMAGE OR DESTRUCTION.........................................................5
CONDEMNATION..................................................................6
DEFAULT.......................................................................6
OPTION TO RENEW...............................................................7
HOLDING OVER..................................................................7
SUBORDINATION.................................................................7
NOTICES.......................................................................7
SECURITY DEPOSIT..............................................................8
LANDLORD'S RULES AND REGULATIONS..............................................8
LANDLORD'S RIGHT TO PERFORM TENANT'S COVENANTS................................8
LIENS.........................................................................9
WASTE.........................................................................9
INSPECTION BY LANDLORD........................................................9
SURRENDER OF PREMISES.........................................................9
WAIVER OF NOTICE..............................................................9
ESTOPPEL CERTIFICATE..........................................................9
LIMITATION OF LIABILITY......................................................10
RIGHTS OF LANDLORD; NON-WAIVER...............................................10
BROKER.......................................................................10
ENTIRE AGREEMENT; AMENDMENT..................................................10
NOTICE OF LEASE..............................................................10


EXHIBIT A - LEGAL DESCRIPTION
EXHIBIT B - TENANT IMPROVEMENT ALLOWANCE
EXHIBIT C - TENANT IMPROVEMENTS (Floor Plan, Detail by ________)




<PAGE>

                                 LEASE AGREEMENT

LEASE AGREEMENT made and entered into as of May 24, 2001, between 16 Commercial
Street Associates, LLC (hereinafter known as "Landlord"), whose principal place
of business is 431 Orange Street, New Haven, Connecticut 06511, and CuraGen
Corporation (hereinafter known as "Tenant") whose principal place of business is
555 Long Wharf Drive, 11th Floor, New Haven, Connecticut 06511.

                                    PREMISES

The Landlord, in consideration of the covenants, conditions, agreements and
stipulations of the Tenant expressed, does hereby lease the following Premises,
the improvements, buildings and land known as 16 Commercial Street, Branford,
Connecticut 06405. The Premises is also described in Exhibit A of the Lease.

                                  TERM AND USE

The Term of the Lease and the estate hereby granted (collectively the "Term of
the Lease") shall commence June 1, 2001 (hereinafter known as the "Commencement
Date") and shall end on May 31, 2006 (hereinafter known as "End of Term"). The
Tenant shall have the option to terminate this Lease on June 1, 2004. The Tenant
must give written Notice to the Landlord of its option to terminate by December
1, 2003, time being of the essence. If the Tenant elects to terminate this
Lease, the Term of the Lease shall continue month-to-month after June 1, 2004,
until the Landlord has signed a lease for the Premises with a new tenant. The
Landlord shall use diligent efforts to secure a new tenant. Rent shall continue
as scheduled herein until the Landlord has signed a lease with a new tenant.

The Premises shall be used by the Tenant for office and lab use. Landlord is its
reasonable discretion reserves the right to limit uses that would constitute and
environmental concern, disturb the quiet enjoyment of other tenants of the
Landlord, or overtax the capacity of the Premises.

                                      RENT

The Rent under this Lease for the Term hereof shall begin on the Commencement
Date and stop at the End of Term. Rent shall include the Base Rent and Common
Area Charges.

1. Base Rent shall starting on the Commencement Date shall be paid as follows:

     From June 1, 2001 to May 31, 2004, the Base Rent is $125,000 per year,
payable in equal installments of $10,416.67 per month. From June 1, 2004 to May
30, 2006, Base Rent is $135,000 per year, payable in equal installments of
$11,250 per month.

2. In addition to Base Rent, the Tenant shall pay the Landlord for all expenses
with respect to the operation, management, and maintenance of the interior and
exterior of the building, the




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grounds, and all areas incidental to the Premises, hereinafter referred to as
"Common Area Charges." The costs shall include such items as, but not limited
to, real estate taxes, all property insurance, sewer taxes or usage fees, water
usage fees, landscape maintenance, snow removal, security, administrative costs,
management fees, roof repairs that result from the Tenant's improvements,
general maintenance and repairs (other than those for which Tenant is
responsible, referred to as "Tenant's Repairs"), and contractor fees. Common
Area Charges shall exclude depreciation, interest and amortization payments on
any mortgage or other indebtedness of Landlord, capital expenditures, leasing
commissions, structural repairs, and expenses reimbursed to the Landlord by
property insurance.

During the first lease year, the Tenant shall pay $2,500 per month in addition
to Base Rent (hereinafter referred to as "CAC Contribution") towards the Common
Area Charges. The Landlord will reconcile the difference between the CAC
Contribution and the Common Area Charges twice during each Lease year. Also, the
monthly CAC Contribution will be adjusted at the end of each Lease year by the
Landlord to reflect the projected costs for the upcoming year. The Landlord will
provide notice of the new CAC Contribution for the upcoming lease year.

3. The Rent shall be paid to the Landlord at the address specified herein, or at
such other place as the Landlord may designate, in lawful money of the United
States of America, as and when the same shall become due and payable and without
abatement of offset and without notice or demand therefor.

4. If any installment of Rent as provided for in this Lease is not received at
the Landlord's address within (10) ten days after the same is due and payable,
the Tenant shall pay an additional amount equal to (5%) five percent of the
monthly Rent so due.

5. As used herein, "Lease Year" shall mean the period commencing on the
Commencement Date and ending on the End of Term, including twelve consecutive
calendar months.

                                TENANT'S REPAIRS

Tenant agrees to provide and pay for all ordinary and necessary maintenance and
repairs of the interior and exterior of the Premises including, but not limited
to, lighting tubes, ballasts, lavatory fixtures and accessories, all glass, all
doors, exit signage, janitorial service, refuse and trash removal, heating and
air conditioning, electrical, plumbing, and all systems in a professional
manner.

The Landlord will contract, on behalf of the Tenant, for snow plowing,
shoveling, sanding, salting of sidewalks, entrances, stairs and stoops, as well
as to be certain that the parking areas are safe for use by the Tenant's
employees, visitors and invitees. These costs shall be reimbursed by the Tenant
to the Landlord through the Common Area Charges.

                               LANDLORD'S REPAIRS

The Landlord shall contract for landscaping and snow removal service. These
costs shall be reimbursed by the Tenant to the Landlord through the Common Area
Charges. So long as no Default shall have occurred and be continuing hereunder,
the Landlord, at its own expense, shall


                                       2

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provide all structural repairs and replacements. Unless such repairs or
replacements shall be required by reason of the Tenant Improvements or
equipment, the default by Tenant in any of its obligations, or the negligence or
willful misconduct of the Tenant, its officers, employees, contractors, agents,
or invitees, in which the Tenant shall reimburse the Landlord for all such costs
and expenses within (10) days of written demand therefor.

                                    INSURANCE

1. At all times during the term of this lease, the Landlord shall insure the
Premises against loss or damage by fire, flood, and such other casualties, rent
loss, in such amount as the Landlord shall deem appropriate. The Tenant shall
reimburse the Landlord for this expense as part of the Common Area Charges.

2. The Tenant shall not commit or permit any violation of the policies carried
by the Landlord, or do or permit anything to be done, or keep or permit anything
to be kept, on or in the Premises, which in case of any of the foregoing, could
result in the termination of such insurance policies, could adversely affect the
Landlord's right of recovery under any such policies, or would result in the
refusal by insurance companies to insure the Premises in the amounts
satisfactory to the Landlord. If any such action by the Tenant shall result in
an increase in the rate of insurance premiums, the Tenant shall pay the increase
to the Landlord upon demand.

3. At all times during this Lease, the Tenant shall insure the Tenant's
Improvements, and the Tenant's Property against loss or damage by fire, flood,
and such other casualties equal to the full replacement value. The tenant will
keep in full force and effect a policy of public liability and property damage
insurance in which the limits shall initially be less than two million dollars
($2,000,000) combined single limit, three million dollars general aggregate
($3,000,000), such limits to be increased as reasonably specified by the
Landlord. The Tenant shall also carry plate glass window insurance and otherwise
be responsible for the same when damaged during the term of this Lease. During
any time when Tenant shall be making alterations or improvements to the
Premises, the Tenant shall keep in full force and effect a policy of completed
value builder's risk insurance (on an "installations floater"), including
building materials, covering loss from damage from fire, lightening, extended
coverage perils, vandalism and malicious mischief, and perils in an amount not
less than the final cost of such alterations or improvements.

4. All insurance policies provided by the Tenant shall be effected under valid
and enforceable policies in form and substance then standard in the State of
Connecticut, issues by insurers having an "AM Best" rating of A- or better.
Within (30) thirty days of the Commencement Date, the Tenant shall provide
certificates to the Landlord of the insurance. All such insurance policies shall
contain an agreement by the insurers that such policies shall not be canceled,
amended, or otherwise modified without (30) thirty days written notice to the
Landlord, and the Landlord's rights and interests under such policies shall not
be subject to cancellation by reason of any act or omission of the Tenant. All
insurance policies provided by the Tenant shall name the Landlord and Landlord's
mortgage lenders as additional insured as their interests may appear.

5. Tenant shall indemnify and hold the Landlord harmless against any liability
or expense, including reasonable attorney's fees, on account of any accident or
injury to the Tenant, the Tenant's employees, servants, agents, customers,
invitees, licensees, contractors, or visitors, who


                                       3

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may be injured by the Tenant or on the Premises. The foregoing shall not extend
to the gross negligence of the Landlord.


                          ALTERATIONS AND IMPROVEMENTS

1. The Tenant shall not make or have made alterations, improvements,
decorations, installations and substitutions (collectively called "Tenant's
Improvements") in, of or to the Premises without the prior written consent of
the Landlord. Approval by Landlord shall not be unreasonably withheld. Unless
otherwise specified, any improvements or alterations in the Premises made by
Tenant (including without limitation permanent partitions, wall paneling and
lighting fixtures, but excepting the Tenant's Property, shall be and remain upon
and be surrendered with the Premises at the End of Term. If the Landlord
requests the removal of any of the Tenant's Improvements, including telephone
and computer cabling, the Tenant shall in good workmanlike manner remove said
improvements at the End of Term.

2. The Tenant shall obtain all necessary permits and certificates for the
commencement and prosecution of the Tenant's Improvements. The Tenant's
Improvements shall not constitute the basis for a claim against the Landlord,
nor a lien or charge upon or against the Premises. If at any time any such claim
or charge shall be filed against the Premises, the Tenant shall cause such
claim, lien or charge to be properly released of record. The Tenant shall pay
for all materials constituting Tenant's Improvements, and the Tenant agrees that
none of such materials shall be at any time subject to any lien, security
interest, charge, installment sales contract, by any other person, firm or
corporation whether created voluntarily or involuntarily.

                 ENVIRONMENTAL COMPLIANCE AND INDEMNIFICATIOINS

1. "Environmental Laws" shall mean any and all statutory, regulatory, or
decisional law pertaining to the protection of the environment or to any
Polluting Substance, including Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), the Resource Conservation and
Recovery Act of 1976 (RCRA), and Title 22a "Environmental Protection" of the
Connecticut General Statutes, including Sections 22a-448 through 22a-457, state
and Federal laws concerning underground storage tanks, the Federal Clean Air
Act, 42 USAA Section 7401 et. seq. state law concerning air pollution, Conn.
Gen. Statutes Section 22a-174 et. Seq.; the Federal Clean Water Act, 33 USC
Section 1251 et. seq. And state and Water Pollution Control Act, Conn. Gen.
Stat. Chapter 446k, and any as amended from time to time. The term "Polluting
Substance" shall mean any toxic, polluting waste or substance, determined by any
agency with jurisdiction to pose a present or potential hazard to human health
or the environment.

2. The Tenant shall not cause or permit any Polluting Substance to be generated,
recycled, refined, transported, treated, stored, disposed, handled, processed,
produced or released on the Premises, except in compliance with all applicable
laws and regulations, including the Environmental Laws. The Tenant covenants and
agrees to be responsible for all costs and penalties arising from non-compliance
with the Environmental Laws, permits, or orders of any agency with jurisdiction
that may impair the Premises or third parties. If the event of a release of a
Polluting Substance caused by Tenant's activities, the Tenant shall notify the
Landlord and the appropriate governmental agency within (24) hours of the
release. The Tenant covenants and


                                       4

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agrees to forever indemnify and hold the Landlord harmless from all costs or
liabilities, including legal and consulting expenses, arising from a violation
of the foregoing. The Environmental Compliance shall survive the expiration or
termination of this Lease, and be governed and construed under the laws of the
State of Connecticut.

                                TENANT'S PROPERTY

Any trade fixtures, equipment and other personal property installed in or
attached to the Premises by the Tenant, shall remain the property of the Tenant
and may be removed by the Tenant at any time during this lease. The Tenant shall
pay for the cost or repairing any damages to the Premises resulting from such
installation or removal. The Landlord shall not be liable to the Tenant or any
person or company for damage or theft to the Tenant's Property.

                               UTILITIES AND FUEL

The Tenant agrees to pay all charges made by any utility company for services
furnished to the Premises during the term of this Lease, including, but not
limited to, electricity, gas, water, sewer, telephone, and cable television.

                            ASSIGNMENT AND SUBLETTING

The Tenant agrees not to assign or in any way encumber this Lease, nor sublet
the Premises, or any part hereof, without obtaining prior written consent of the
Landlord, which shall not be unreasonably withheld. In the event the Landlord
consents to an assignment, by reason of a sale of the Tenant, or for any other
purpose, the Tenant will remain liable for full performance of the lease. In the
event of an assignment, or sale of the Tenant, all rights and guarantees
provided to the Landlord will survive the assignment.

                              DAMAGE OR DESTRUCTION

1. In the event that the Premises, other than Tenant's Improvements or Tenant's
Property, is damaged by fire or other insured casualty, but the Tenant shall
continue to have reasonably convenient access, and no portion shall be rendered
unfit for use and occupancy, the Landlord shall repair such damage with
diligence. During the repair period, the Rent shall not be abated or suspended.

2. In the event that the Premises, other than Tenant's Improvements or Tenant's
Property, are damaged or destroyed by fire or other insured casualty, and the
Tenant shall not have reasonably convenient access, or rendered unfit for use
and occupancy, and if in the sole judgment of the Landlord the damage may be
repaired within one hundred and eighty days (180) after the occurrence, then the
Landlord shall notify the Tenant within thirty (30) days after the occurrence,
and shall repair such damage with diligence. If the Premises does not have
reasonably convenient access or some portion of the Premises, or the whole of
the Premises is rendered unfit, the Rent shall be appropriately abated during
the period until tenant regains occupancy. The Tenant shall have the right to
terminate the Lease, within ten (10) days notice, if


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the Landlord cannot repair the damage and receive appropriate authority for Use
and occupancy after the one hundred and eighty (180) day period, except for
delays caused by acts of god, strikes, or government regulation. No damages,
compensation or claim shall by payable to the Landlord or the Tenant, or any
other person, by reason of inconvenience, loss of business, or annoyance arising
from any damage, or repair thereof.

                                  CONDEMNATION

If the building, or so much of the building as is necessary for the Tenant's Use
and occupancy for the purpose set forth herein, shall be taken by condemnation
or in any other manner, then the term of this lease shall terminate as of the
date title vests in the taking authority, and the Rent shall be apportioned as
of such date. The Tenant shall have the right in any condemnation proceeding to
any award payable for the Tenant's moving expenses and the value of the Tenant's
Property. The Tenant shall have no other right to any award for taking of the
land, the contract value of this Lease, and rights to all such rewards shall be
retained by the Landlord.

                                     DEFAULT

1. Any of the following shall constitute "Default" under this Lease: whenever
the Tenant fails to pay Rent or Common Area Charges, or any other charge payable
by Tenant to the Landlord, under this Lease within fifteen (15) days of it being
due. Or, whenever the Tenant fails to obtain or maintain the required insurance
under this Lease, or if the Tenant does, or fails to do, any other action
provided for by this Lease, and does not remedy the same within thirty (30)
days.

2. In the event of Default, the Landlord shall have the immediate right, at its
election, to terminate the term of the Lease by giving the Tenant ten (10) days
notice of the Landlord's election to terminate. The Landlord may elect to take
possession and remove the property and possessions of the Tenant, and the same
may be stored in a public warehouse, at the cost for the account of the Tenant,
and without notice or resort to legal process. The Landlord shall not be guilty
of trespass, or be liable for loss or damage occasioned thereby.

3. If the Landlord elects to take possession, the Landlord shall be under no
obligation to re-lease the whole or part of the Premises on behalf of the
Tenant, for period equal to, greater or less than, the remainder of the term of
this Lease, and at such rent and upon such terms as the Landlord shall deem
reasonable. The Landlord shall be entitled to the rent upon such re-leasing,
whether or not such rent is in excess of the Rent.

4. If the Landlord elects to re-enter and take possession of the Premises, and
whether or not the Landlord has terminated this lease, or re-leased the
Premises, the Tenant shall pay to the landlord as liquidated damages, within ten
(10) days of written demand, all unpaid Rent for the Term of the Lease,
including Common Area Charges, all expenses of maintaining the Premises while
vacant, all expenses, including reasonable attorney's fees, incurred by Landlord
in recovering possession, re-leasing the same, and collecting Rent, all costs of
repairs and decorations to re-lease the Premises, and all brokerage commissions
in re-leasing the Premises. Notwithstanding the foregoing, the Landlord shall
reimburse the Tenant that portion of the unpaid rent that is recovered by
Landlord's releasing of the Premises.


                                       6

<PAGE>

                                 OPTION TO RENEW

The Tenant shall have one option to extend the Term of this lease by five years,
beginning June 1, 2006, and continuing through May 31, 2011. Such renewal shall
be upon the same terms and conditions as are applicable to the first term,
except for Base Rent. The annual Base Rent during the Option will be equal to
the Fair Market Value for similar property in the area. The Tenant's right to
exercise the Option shall be contingent upon this Lease being in full force
without Default, the Tenant's giving notice to the Landlord of its intent by
September 1, 2005, and the mutual agreement by the Landlord and Tenant to Fair
Market Rent by December 1, 2005.

                                  HOLDING OVER

The Tenant shall pay to the Landlord Rent equal to one hundred and twenty-five
(125%) percent of the Rent payable at the End of Term. The hold-over rent shall
be paid in equal monthly installments. The provisions of this article shall not
constitute a waiver or limit any other rights and remedies of the Landlord
provided herein or at law.

                                  SUBORDINATION

This Lease and all rights of the Tenant hereunder are subject to and subordinate
to any mortgage or ground lease made by the Landlord, which affect the Premises.
It is the intention of the Landlord and Tenant that this provision be
self-operative, and no further instrument shall be required to effect a
subordination of this Lease. Upon demand, however, the Tenant shall at any time
execute, acknowledge and deliver to the Landlord any subordination agreement to
any future mortgagee or ground lessor. If in the mortgaging of the Premises by
the Landlord, any mortgagee requests modifications to the Lease, and such
modification does not materially increase the obligations of the Tenant, the
Tenant shall not withhold or delay consent to such modification.

                                     NOTICES

Whenever notice is required by conditions of this lease, such notice shall be
given or served in person, or sent by a nationally recognized overnight carrier,
or by registered or certified mail, return receipt requested, and addressed as
follows:

To Landlord at
--------------
Richard Michaud
16 Commercial Street Associates, LLC
C/o Michaud Company
431 Orange Street
New Haven, Connecticut  06511


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To Tenant at:
-------------
Terrie B. Atkinson, Director, Financial Planning
CuraGen Corporation
555 Long Wharf Drive, 11th floor
New Haven, Connecticut  06511

Or to such other person or address as either party shall have specified for
itself by notice to the other party in the manner set forth previously.

                                SECURITY DEPOSIT

Contemporaneously with the execution of this Lease, the Tenant has deposited
with the Landlord the sum of ten thousand four hundred and sixteen dollars
($10,416.67). The security deposit will be held by the Landlord, without
liability for interest except as required by law, as security for the
performance by the Tenant of all terms of this Lease. The Security Deposit shall
not be used to pay Rent at the End of Term. The Security Deposit shall be
returned to the Tenant within thirty (30) days after vacating the Premises with
a final accounting of offsets, if any.

                        LANDLORD'S RULES AND REGULATIONS

No unregistered cars, trucks or trailers may be present upon the Premises
without prior written permission of the Landlord. Outside storage shall be
limited to incidental materials used in the operation of the Tenant's business.
The Tenant shall limit the outside storing of cars, trucks, vans, truck bodies,
storage sheds, boats, trailers, or storage containers. Any and all materials
handling equipment shall not mark or damage the floors and paving. No animals of
any kind shall be housed on the Premises, except seeing eye dogs or similar
animals. While the Landlord will contract for snow removal, the Tenant is
responsible for shoveling and sanding sidewalks, stoops, entranceways, and to be
certain all areas are safe. The Tenant agrees to notify or call the Landlord
within eight (8) hours of an emergency, such as fire, explosion, criminal
activity, environmental hazard, storm damage, and similar events.

                 LANDLORD'S RIGHT TO PERFORM TENANT'S COVENANTS

The Landlord may make any payment or fulfill any obligation on behalf of the
Tenant regarding the repair and maintenance of the Premises. The Landlord shall
not be obligated to perform any of Tenant's covenants. The Tenant is not
released of its obligations thereto if the Landlord performs any of the Tenant's
obligations. If the Landlord makes any payment in performance of the Tenant's
obligations, the payment shall become Rent as used in this lease, together with
interest of eighteen percent (18%) per year or the maximum rate allowable by
law.


                                       8

<PAGE>

                                      LIENS

The Tenant shall not suffer or permit any mechanics liens, materialman's liens
or other liens, including, but not limited to, real estate broker liens, to be
filed against the Premises. If any such lien shall be filed, the Tenant shall
cause the same to be discharged of record within thirty (30) days of the receipt
of notice by the Tenant of the filing of the same.

                                      WASTE

The Tenant covenants and agrees not to do or suffer any waste, damage,
disfigurement or injury to the Premises of any part hereof.

                             INSPECTION BY LANDLORD

Upon reasonable notice, the Tenant agrees to permit the Landlord, and its
representatives, to enter the Premises. The Landlord shall have the right to
exhibit the same for the purpose of sale. And during the last year of the Lease,
the Landlord shall have the right to exhibit the Premises for the purpose of
leasing or for a sale.

                              SURRENDER OF PREMISES

On the last day of this Lease, or upon any earlier termination, the Tenant shall
quit and surrender the Premises to the Landlord, in good order, condition and
repair. The Tenant shall remove all Tenant's Property, and shall remove those
portions of the Tenant's Improvements designated by the Landlord, and repair any
damage incidental thereto such removal.

                                WAIVER OF NOTICE

Intentionally omitted.


                              ESTOPPEL CERTIFICATE

The Tenant agrees to deliver to the Landlord's written request, within ten (10)
days of receipt, a written certificate, in recordable form, ratifying this
Lease, including all terms and conditions requested by such certificate.


                                       9

<PAGE>

                             LIMITATION OF LIABILITY

Anything within this Lease to the contrary notwithstanding, the Tenant agrees
that it shall look solely to the estate and property of the Landlord in the
Premises for the collection of any judgment, or other judicial process,
requiring the payment of money by the Landlord, and for no other assets of the
Landlord or of any partner in the Landlord.

                         RIGHTS OF LANDLORD; NON-WAIVER

No right or remedy conferred upon the Landlord is intended to be exclusive of
any other right or remedy, and every right and remedy shall be cumulative. The
failure of Landlord to insist upon strict performance of any provision of this
Lease shall not be construed as a waiver or relinquishment thereof for the
future. Receipt by the Landlord of Rent, with knowledge of a breach of any
provision shall not be deemed a waiver of such breach.

                                     BROKER

The Tenant represents that no broker or agent participated with Tenant in this
transaction. The Tenant agrees to indemnify and hold Landlord harmless from and
against any claim of any other broker or agent.

                           ENTIRE AGREEMENT; AMENDMENT

This Lease and all Exhibits attached constitute the entire agreement between the
Tenant and the Landlord. This lease may not be modified except in writing,
signed by both parties. The Tenant by entering into actual possession of the
Premises shall be conclusively deemed to have agreed that the Landlord has
provided its obligations.

                                 NOTICE OF LEASE

This lease shall not be recorded on the Branford land records. Upon written
request by either party, the other party shall execute a Notice of Lease, in
recordable form, satisfying the requirements of Section 47-19 of the Connecticut
General Statues, as amended.


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<PAGE>

IN WITNESS WHEREOF, the Landlord and the Tenant have caused this Lease to be
duly executed the day and year written on the first page.

Landlord:                                           Signed, sealed and delivered
                                                    in the presence of:
                                                    ----------------------------

20 Commercial Street Associates, LLC
---------------------                               -------------------------
Richard Michaud
Member
-------------------------                           -------------------------
Frederick Petrella
Member

Tenant:

CuraGen Corporation
-------------------------                           -------------------------
David Wurzer

Executive Vice President and Chief Financial Officer
-----------------------                             -------------------------
Terrie B. Atkinson
Director of Financial Planning


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<PAGE>

                                    EXHIBIT A

                        - Legal Description of Premises -



<PAGE>

                                    EXHIBIT B

                        - Tenant Improvement Allowance -

The Landlord shall provide to the Tenant a cash allowance of $26,000. The
allowance will be paid during the first three months of the lease term. The
allowance shall be used by the Tenant to offset the cost of the Tenant
Improvements the Tenant will install, at its expense, to the Premises. The
Tenant will renovate the Premises for office and/or lab space at its expense,
including exterior windows. The improvements tenant will install are detailed by
Exhibit C.

At its expense, the Landlord will repaint/repair the exterior of the building
and make repairs to the exterior landscaping. The Tenant will be responsible for
providing all interior painting and repairs.



<PAGE>

                                    EXHIBIT C

                               Tenant Improvements

                                   Floor Plan

                       Construction Detail By ____________