Statement re: Patent

PROTEOME SCIENCES plc

PRESS RELEASE

Notice of Intention to Grant European Patent on Isobaric Tandem Mass Tags® (TMT®)

18th December 2006. Proteome Sciences plc ("Proteome Sciences") is pleased to
announce that the European Patent Office has today posted, in relation to Rule
51(4), that the official Notice of Intention to 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 will be published
on 27th December, 2006. The Notice of Intention to Grant is the final stage of
patent examination and represents the form in which the patent will be granted.
It is expected that the final issuance will be completed early in 2007. This
follows grants of the corresponding cases in Australia and New Zealand and of
the TMT2 product in Canada. The European Patent contains broad claims to
isobaric mass tags - a class of small chemical reagents used to label proteins
- and methods of their use.

As submitted, the allowed claims are not limited in respect of the level of
multi-plexing of the isobaric mass tags. At this time, Proteome Sciences
considers that the most appropriate configurations to be duplex and six-plex
sets of tags. The six-plex set of TMT® reagents contains six different isobaric
mass tags that are used to label the proteins extracted from individual
samples. After labelling, the samples are mixed and the protein content and
relative abundance determined by mass spectrometry in a single experiment. This
enables a significant increase in the throughput and accuracy of biomarker
discovery without compromising the sensitivity of the individual results.

Isobaric mass tags are a new field of technology and published data is not
readily available. Proteome Sciences estimates that isobaric mass tags already
account for around 50% of the current $10m to $20m per annum chemical tagging
market and the market for these tags is growing disproportionately fast. Only
approximately 50% of existing mass spectrometers (c. 25,000 units) are able to
use isobaric mass labels. Sales of new MS instruments, most of which can now
use isobaric mass tags, are forecast to at least double in the next five years.
Spending on proteomics research tools is also forecast to grow at double digit
CAGR from a base of around $400 million in 2004. This will be further enhanced
by a broad range of applications for isobaric mass tags in life sciences. QC,
food, pharmaceuticals and environmental as the flexibility and power of the
tags are better appreciated by a much wider audience.

In early 2005, our initial estimates for isobaric mass tags projected sales
into hundreds of $millions over the TMT® patent life. These figures now appear
to be conservative and with three products already available, we estimate that
the market size may have increased to between $600m and $1.4bn and Proteome
Sciences fully anticipates receiving royalties from its patents in isobaric
mass tags over this period.

Commenting on the Notice of Intention to Grant, Christopher Pearce, CEO of
Proteome Sciences said:

"The posting today from the European Patent Office in respect of TMT® isobaric
mass tags and methods for their use in Europe is a major milestone for the
company. In conjunction with our other granted and pending patents to isobaric
mass tag technology, this provides clear protection for TMT® in the major
economic territories allowing us to leverage maximum value from the
considerable investment in their development.

Similar progress is being made with the TMT® patent process in the USA, and we
would expect that the next stage will be the Notice of Allowance for our US
patent application.

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 and value of
these reagents across the life sciences sector. We continue to develop enhanced
TMT® applications to support our own biomarker discovery, validation and
measurement effort to expand the ProteoSHOP® offering for our customers.

The significance and impact of these latest developments have undoubtedly
increased the profile and economic value of isobaric mass tags and these need
to be fully incorporated into the TMT® licence negotiations with the relevant
parties. Negotiations for the conclusion of the TMT® licence are continuing and
the company believes that this process will move forward over the next few
weeks and should increase the return to 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 .

Enquiries:

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]