Notifiable Interest

22 May 2007 15:50

Proteome Sciences PLC ("the Company") Notifiable Interest

A form TR-1 containing the following information has been received by the Company.

TR-1 Notification of major interests in shares

1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached:

Proteome Sciences PLC

2. Reason for the notification

An acquisition or disposal of voting rights

3. Full name of person(s) subject to the notification obligation:

Sanofi-Aventis Deutschland GmbH

4. Full name of shareholder(s) (if different from 3):

N/A

5. Date of the transaction (and date on which the threshold is crossed or reached if different):

15 May 2007

6. Date on which issuer notified:

21 May 2007

7. Threshold(s) that is/are crossed or reached:

12%

8. Notified details:

A: Voting rights attached to shares

Class/type Situation previous to Resulting situation after the triggering of shares Triggering transaction transaction if possible Notification required under DTR transitional using ISIN provision 7 CODE Number of Number of Number of Number of voting % of voting Shares Voting shares rights rights Rights Direct Direct Indirect Direct Indirect

GB0003104196 16,384,649 16,384,649 14,982,811 14,982,811 11.40%

B: Financial Instruments

Resulting situation after the triggering transaction Type of Expiration Exercise/ Number of voting rights that may % of financial date Conversion be acquired if the instrument is voting instrument Period/ Date exercised/ converted rights N/A N/A N/A N/A N/A Total (A+B)

Number of voting rights % of voting rights

14,982,811 11.40%

9. Chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held, if applicable:

N/A10. Name of the Proxy holder:N/A

11. Number of voting rights proxy holder will cease to hold:

N/A

12. Date on which proxy holder will cease to hold voting rights:

N/A

13. Additional information:

N/A

14. Contact name:

Juergen Blieke or Reiner May

15. Contact telephone number:

0049 69 305 4703 or 0049 69 305 80202