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                                                                   EXHIBIT 10.35

                          TRANSKARYOTIC THERAPIES, INC.

                       Nonstatutory Stock Option Agreement
               Granted Under 2002 Stock Incentive Plan, as amended

1.    Grant of Option.

      This agreement evidences the grant by Transkaryotic Therapies, Inc., a
Delaware corporation (the "Company"), on ______, 200[ ] (the "Grant Date") to
[_________], an [employee], [consultant], [director] of the Company (the
"Participant"), of an option to purchase, in whole or in part, on the terms
provided herein and in the Company's 2002 Stock Incentive Plan, as amended (the
"Plan"), a total of [_____] shares (the "Shares") of common stock, $0.01 par
value per share, of the Company ("Common Stock") at $[_________] per Share.
Unless earlier terminated, this option shall expire at 5:00 p.m., Eastern time,
on [_______] (the "Final Exercise Date").

      It is intended that the option evidenced by this agreement shall not be an
incentive stock option as defined in Section 422 of the Internal Revenue Code of
1986, as amended, and any regulations promulgated thereunder (the "Code").
Except as otherwise indicated by the context, the term "Participant", as used in
this option, shall be deemed to include any person who acquires the right to
exercise this option validly under its terms.

2.    Vesting Schedule.

      This option will become exercisable ("vest") as to [___]% of the original
number of Shares on the [first anniversary] of the Grant Date and as to an
additional [____]% of the original number of Shares at the end of each
successive [three-month] period following the first anniversary of the Grant
Date until the [fourth] anniversary of the Grant Date.

      The right of exercise shall be cumulative so that to the extent the option
is not exercised in any period to the maximum extent permissible it shall
continue to be exercisable, in whole or in part, with respect to all Shares for
which it is vested until the earlier of the Final Exercise Date or the
termination of this option under Section 3 hereof or the Plan.

3.    Exercise of Option.

      (a) Form of Exercise. Each election to exercise this option shall be (a)
in writing, signed by the Participant, received by the Company at its principal
office, accompanied by this agreement, or (b) in accordance with the Company's
electronic option exercise policies, and in either case, with payment in full in
the manner provided in the Plan. The Participant may purchase less than the
number of shares covered hereby, provided that no partial exercise of this
option may be for any fractional share.

      (b) Continuous Relationship with the Company Required. Except as otherwise
provided in this Section 3, this option may not be exercised unless the
Participant, at the time he or she exercises this option, is, and has been at
all times since the Grant Date, an employee, officer or director of, or
consultant or advisor to, the Company or any other entity the employees,
officers, directors, consultants, or advisors of which are eligible to receive
option grants under the Plan (an "Eligible Participant"). The Participant shall
not have any rights in respect to the Shares as to which this option shall not
have been exercised and payment made as provided herein. The

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Participant shall not have any rights to continued employment with the Company
or any of its subsidiaries by virtue of the grant of this option.

      (c) Termination of Relationship with the Company. If the Participant
ceases to be an Eligible Participant for any reason, then, except as provided in
paragraphs (d) and (e) below, the right to exercise this option shall terminate
within thirty days after such cessation (but in no event after the Final
Exercise Date), provided that this option shall be exercisable only to the
extent that the Participant was entitled to exercise this option on the date of
such cessation. Notwithstanding the foregoing, if the Participant, prior to the
Final Exercise Date, violates the non-competition or confidentiality provisions
of any employment contract, confidentiality and nondisclosure agreement or other
agreement between the Participant and the Company, the right to exercise this
option shall terminate immediately upon such violation.

      (d) Exercise Period Upon Death or Disability. If the Participant dies or
becomes disabled (within the meaning of Section 22(e)(3) of the Code) prior to
the Final Exercise Date while he or she is an Eligible Participant and the
Company has not terminated such relationship for "cause" as specified in
paragraph (e) below, this option shall be exercisable, within the period of one
year following the date of death or disability of the Participant, by the
Participant (or in the case of death by an authorized transferee), provided that
this option shall be exercisable only to the extent that this option was
exercisable by the Participant on the date of his or her death or disability,
and further provided that this option shall not be exercisable after the Final
Exercise Date.

      (e) Discharge for Cause. If the Participant, prior to the Final Exercise
Date, is discharged by the Company for "cause" (as defined below), the right to
exercise this option shall terminate immediately upon the effective date of such
discharge. "Cause" shall mean willful misconduct by the Participant or willful
failure by the Participant to perform his or her responsibilities to the Company
(including, without limitation, breach by the Participant of any provision of
any employment, consulting, advisory, nondisclosure, non-competition or other
similar agreement between the Participant and the Company), as determined by the
Company, which determination shall be conclusive. The Participant shall be
considered to have been discharged for "Cause" if the Company determines, within
30 days after the Participant's resignation, that discharge for cause was
warranted.

4.    Withholding.

      No Shares will be issued pursuant to the exercise of this option unless
and until the Participant pays to the Company, or makes provision satisfactory
to the Company for payment of, any federal, state or local withholding taxes
required by law to be withheld in respect of this option.

5.    Nontransferability of Option.

      This option may not be sold, assigned, transferred, pledged or otherwise
encumbered by the Participant, either voluntarily or by operation of law, except
by will or the laws of descent and distribution, and, during the lifetime of the
Participant, this option shall be exercisable only by the Participant.

6.    Provisions of the Plan.

      This option is subject to the provisions of the Plan, a copy of which is
furnished to the Participant with this option.

      IN WITNESS WHEREOF, the Company has caused this option to be executed
under its corporate seal by its duly authorized officer. This option shall take
effect as a sealed instrument.

                                     TRANSKARYOTIC THERAPIES, INC.

Dated:_________                      By:_____________________________________

                                           Name:_____________________________
                                           Title:____________________________

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                            PARTICIPANT'S ACCEPTANCE

      The undersigned hereby accepts the foregoing option and agrees to the
terms and conditions thereof. The undersigned hereby acknowledges receipt of a
copy of the Company's 2002 Stock Incentive Plan, as amended.

                                                    PARTICIPANT:

                                                    _________________

                                                    Address:___________________

                                                            ___________________

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