GRANT OF EUROPEAN PATENT ON ISOBARIC TANDEM MASS TAGS® (TMT®)

15th May 2007

Proteome Sciences plc (“Proteome Sciences”) is pleased to announce that the European Patent Office has today posted that the Grant for its European patent application in isobaric mass labelling for its tandem mass tags (TMT®) entitled “Selective Acquisition of Mass Markers” Serial No. 01911912.2 (TMT1) will be published on 13th June, 2007. This follows grants of the corresponding cases in Australia, New Zealand and Canada. The European Patent contains broad claims to isobaric mass tags and methods of their use as chemical reagents to label proteins.

The Grant of TMT1 is a major milestone for Proteome Sciences because it will enable the company to approach entities using isobaric mass labels in Europe and to alert them that they can obtain licences from Proteome Sciences for the manufacture or use of any type of isobaric mass tags in their research programmes. These licences will allow revenue to be generated from any applications in the field of isobaric mass tagging.

Commenting on the Grant of TMT1, Christopher Pearce, Chief Executive of Proteome Sciences said:

"The Grant of TMT1 in Europe puts Proteome Sciences in an outstanding position to generate substantial revenues from a combination of licence payments, back-licence payments, product sales and royalties. The market for isobaric tandem mass tags continues to grow disproportionately fast and earlier estimates over the patent lives appear to have considerably underestimated the scale and importance of quantitative mass spectrometry.

The TMT1 and TMT2 patent applications in the USA are in the final stages of processing and we anticipate that these too will be concluded shortly.

New applications for TMT® have and are being developed that will add to this growth. Today we are presenting one such new application at the Biomarker World Congress in Philadelphia, USA where we will demonstrate TMT® labelled plasma reference for MS/MS quantification of individual samples using mass spectrometry.

This heralds the development of a new universal reference material based on TMT® validated with human samples showing dramatic improvement in the reproducibility and comparability of proteomics studies with increased precision in clinical trials. The biological reference materials show exact and reliable absolute quantification for biomarker validation and measurement.

The European Grant today is a major step forward for Proteome Sciences, and we intend to maximise the commercial value of TMT® for our shareholders."