Grant of European Patent

PROTEOME SCIENCES plc                             

                                 PRESS RELEASE                                 

                           Grant of European Patent                            

                     On Isobaric Tandem Mass Tags® (TMT®)                      

15 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."

                                     Ends                                      

Notes to editors:

Proteome Sciences plc

Proteome Sciences, a global leader in applied proteomics, uses high sensitivity
proprietary technologies to detect differentially expressed proteins in
diseases. The protein biomarkers discovered in body fluids or tissues are
validated, developed and commercialised as diagnostic, prognostic or
therapeutic products through strategic alliances and out-licensing.

Through its unique ProteoSHOP® toolbox, Proteome Sciences provides high
sensitivity/high throughput proteomics solutions, including traditional two
dimensional gel-based electrophoresis (2DE) and proprietary gel-free protein
sequence tag technologies (PST®, qPST™& TMT®), to major pharma, biotechnology
and diagnostic companies, to discover and exploit protein biomarkers.
Sensitizer® chemical mass tags have been developed separately as a series of
stand-alone reagents.

For further information please visit www.proteomics.com .

Proteome Sciences plc

Dr. Ian Pike, Business Development Director

Email: [e-mail]

Christopher Pearce, Chief Executive Officer

Email: [e-mail]

Tel: [phone]

Public Relations for Proteome Sciences

IKON Associates

Adrian Shaw

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