Notice of Allowance of TMT1 Patent in Canada

PROTEOME SCIENCES plc

Notice of Allowance of TMT1 Patent in Canada

8 May 2007. Proteome Sciences plc ("Proteome Sciences") is pleased to announce
that it has received the Notice of Allowance for Canadian Patent Application
No. 2,403,114 entitled "Mass Markers" dated 13th April, 2007 ("TMT1"). TMT1 is
the first patent filed describing isobaric mass tags and is part of a series of
patents including TMT2 in Canada that was granted on 21st November, 2006. TMT1
has established a broad set of claims controlling the field of isobaric tandem
mass tagging (Tandem Mass Tags® and TMT®) whilst TMT2 relates to more specific
isobaric mass tag structures and various methods of use. The two patents are
highly complementary, but TMT1, with its early priority and broader claims, is
of greater significance.

The TMT1 Notice of Allowance is very important for Proteome Sciences because it
will enable the company for the first time to approach entities using isobaric
mass labels in Canada 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. Such licenses will allow revenue to be generated
from any applications in the field of isobaric mass tagging.

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

"We are delighted that our first full set of patents covering isobaric tandem
mass tagging (TMT®) have been allowed in Canada. This should be followed up
shortly with similar allowances in Europe and the USA.

In Europe, the patent process for TMT1 is nearly completed with the Rule 51(4)
Notice of Intention to Grant having been published and the patent expected to
be issued in the near future. In the USA, the TMT1 and TMT2 patent applications
are in the final stages of processing and we anticipate that these too will be
concluded shortly.

Having acquired the TMT® technology in 2002, Proteome Sciences was provided
with both the earliest date of invention of isobaric mass tagging and the
patents for the technology. Our goal is to have a full range of TMT® products
launched in the market in the second half of the year. These have been
developed in-house over the last year and, with the issuance of the patents and
the completion of the licensing processes, we will be in the 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.

After the delays, we intend to make the most of the value of TMT® for our
shareholders."

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

Tel: [phone]

Mobile: [phone]

Email: [e-mail]