<PAGE>
Joint Filing Agreement
The undersigned hereby agree that the statement on Schedule 13D with
respect to the Common Stock of Transkaryotic Therapies, Inc. is, and any
amendment thereto signed by each of the undersigned shall be, filed on behalf of
each undersigned pursuant to and in accordance with the provisions of 13d-1(k)
under the Securities Exchange Act of 1934, as amended.
Dated: June 16, 2000
WARBURG, PINCUS EQUITY
PARTNERS, L.P.
By: Warburg, Pincus & Co.,
General Partner
By: /s/ Stephen Distler
------------------------------
Stephen Distler
Partner
WARBURG, PINCUS & CO.
By: /s/ Stephen Distler
------------------------------
Stephen Distler
Partner
E.M. WARBURG, PINCUS & CO., LLC
By: /s/ Stephen Distler
------------------------------
Stephen Distler
Member
<PAGE>
SCHEDULE I
----------
Set forth below is the name, position and present principal occupation of
each of the general partners of Warburg, Pincus & Co. ("WP") and members of E.M.
Warburg, Pincus & Co., LLC ("EMW LLC"). The sole general partner of Warburg,
Pincus Equity Partners, L.P. ("WPEP") is WP. WPEP, WP, and EMW LLC are
hereinafter collectively referred to as the "Reporting Entities". Except as
otherwise indicated, the business address of each of such persons is 466
Lexington Avenue, New York, New York 10017, and each of such persons is a
citizen of the United States.
GENERAL PARTNERS OF WP
----------------------
---------------------------- ---------------------------------------------------
PRESENT PRINCIPAL OCCUPATION IN ADDITION
TO POSITION WITH WP, AND POSITIONS
NAME WITH THE REPORTING ENTITIES
---------------------------- ---------------------------------------------------
Joel Ackerman Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Harold Brown Partner of WP; Member and Senior Managing Director
of EMW LLC
---------------------------- ---------------------------------------------------
W. Bowman Cutter Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Cary J. Davis Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Stephen Distler Partner of WP; Member, Managing Director and
Treasurer of EMW LLC
---------------------------- ---------------------------------------------------
Stewart K. P. Gross Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
<PAGE>
---------------------------- ---------------------------------------------------
Patrick T. Hackett Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Jeffrey A. Harris Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
William H. Janeway Partner of WP; Member and Senior Managing Director
of EMW LLC
---------------------------- ---------------------------------------------------
Douglas M. Karp Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Charles R. Kaye Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Henry Kressel Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Joseph P. Landy Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Sidney Lapidus Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Kewsong Lee Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Jonathan S. Leff Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Reuben S. Leibowitz Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
David E. Libowitz Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Nancy Martin Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Edward J. McKinley Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Rodman W. Moorhead III Partner of WP; Member and Senior Managing Director
of EMW LLC
---------------------------- ---------------------------------------------------
Howard H. Newman Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
<PAGE>
---------------------------- ---------------------------------------------------
Gary D. Nusbaum Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Dalip Pathak Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Lionel I. Pincus Managing Partner of WP; Managing Member, Chairman
of the Board and Chief Executive Officer of EMW LLC
---------------------------- ---------------------------------------------------
John D. Santoleri Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Henry Schacht Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Steven G. Schneider Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
John L. Vogelstein Partner of WP; Member and Vice Chairman of EMW LLC
---------------------------- ---------------------------------------------------
Elizabeth H. Weatherman Partner of WP; Member and Managing Director of EMW
LLC
---------------------------- ---------------------------------------------------
Pincus & Co.*
---------------------------- ---------------------------------------------------
NL & Co.**
---------------------------- ---------------------------------------------------
---------------------
* New York limited partnership; primary activity is ownership interest in WP
and EMW LLC.
** New York limited partnership; primary activity is ownership interest in WP.
As of 6/00
<PAGE>
MEMBERS OF EMW LLC
------------------
---------------------------- ---------------------------------------------------
PRESENT PRINCIPAL OCCUPATION IN ADDITION
TO POSITION WITH EMW LLC, AND POSITIONS
NAME WITH THE REPORTING ENTITIES
---------------------------- ---------------------------------------------------
Joel Ackerman Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Frank M. Brochin (1) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Harold Brown Member and Senior Managing Director of EMW LLC;
Partner of WP
---------------------------- ---------------------------------------------------
W. Bowman Cutter Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Cary J. Davis Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Stephen Distler Member, Managing Director, and Treasurer of EMW
LLC; Partner of WP
---------------------------- ---------------------------------------------------
Tetsuya Fukagawa (2) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Stewart K. P. Gross Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Alf Grunwald (3) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Patrick T. Hackett Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Jeffrey A. Harris Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Roberto Italia (4) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
William H. Janeway Member and Senior Managing Director of EMW LLC;
Partner of WP
---------------------------- ---------------------------------------------------
<PAGE>
---------------------------- ---------------------------------------------------
Douglas M. Karp Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Charles R. Kaye Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Henry Kressel Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Rajiv B. Lall (5) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Joseph P. Landy Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Sidney Lapidus Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Kewsong Lee Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Jonathan S. Leff Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Reuben S. Leibowitz Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
David E. Libowitz Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Nicholas J. Lowcock (6) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
John W. MacIntosh (7) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Nancy Martin Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Edward J. McKinley Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
James McNaught-Davis (6) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Rodman W. Moorhead III Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Howard H. Newman Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
<PAGE>
---------------------------- ---------------------------------------------------
Gary D. Nusbaum Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Dalip Pathak Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Lionel I. Pincus Managing Member, Chairman of the Board and Chief
Executive of EMW LLC; Managing Partner of WP
---------------------------- ---------------------------------------------------
John D. Santoleri Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Henry Schacht Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Steven G. Schneider Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Dominic H. Shorthouse (6) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Melchior Stahl (3) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Chang Q. Sun (8) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
John L. Vogelstein Member and Vice Chairman of EMW LLC; Partner of WP
---------------------------- ---------------------------------------------------
Elizabeth H. Weatherman Member and Managing Director of EMW LLC; Partner of
WP
---------------------------- ---------------------------------------------------
Jeremy S. Young (6) Member and Managing Director of EMW LLC
---------------------------- ---------------------------------------------------
Pincus & Co.*
---------------------------- ---------------------------------------------------
(1) - Citizen of France
(2) - Citizen of Japan
(3) - Citizen of Germany
(4) - Citizen of Italy
(5) - Citizen of India
(6) - Citizen of United Kingdom
(7) - Citizen of Canada
(8) - Citizen of China
<PAGE>
* New York limited partnership; primary activity is ownership interest in WP
and EMW LLC
As of 6/00
