ISSUANCE OF TMT^® PATENT IN CANADA

13 December 2006

Proteome Sciences plc is pleased to announce that it has today received the official Letters Patent for Canadian Patent Number 2,460,131 entitled "Mass Markers" which was granted on November 21st 2006. The claims of the issued patent relate to specific isobaric mass tag structures which represent one class of Proteome Sciences Tandem Mass Tag^® (TMT^®) technology. The patent term is 20 years from 16th September 2002.

There are currently two international patent applications relating to TMT^®. Canadian Patent Number 2,460,131 was the second TMT^® patent (TMT2) to be filed and claims isobaric mass tags with peptide structures and various methods of their use. The earlier TMT^® patent (TMT1) is in process of prosecution at the Canadian Intellectual Property Office.

Commenting on the issuance Christopher Pearce, Chief Executive of Proteome Sciences said:

"Recent events, including the launch of isobaric mass tags by Perkin Elmer (ExacTags) and new applications for the isobaric iTRAQ mass tags by Applied Biosystems highlight the growing recognition of the importance of these reagents across life sciences research. We have been working on the development of a number of TMT functions to enhance our own biomarker discovery, validation and measurement efforts and to improve the ProteoSHOP® offering to our customers with particular emphasis on supporting applications in pre-clinical pharmaceutical discovery and clinical trials of new drugs.

The issuance of one of the TMT^® family of patents in Canada is another significant milestone in the company's development. It validates the patentability of the TMT^® isobaric mass tags in a sizeable economic market and underpins the value of our pending TMT1 and TMT2 applications in other territories.

This has increased the profile and economic value of our isobaric mass tags and will be incorporated into the TMT^® licence negotiations.

We anticipate that issuance of the first Canadian patent relating to the TMT^® technology will shortly be followed by further progress with both TMT1 and TMT2 applications in other territories."