NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, DIRECTLY OR INDIRECTLY, IN WHOLE OR IN PART, TO US PERSONS OR INTO OR WITHIN THE UNITED STATES, AUSTRALIA, CANADA, THE REPUBLIC OF SOUTH AFRICA OR JAPAN, OR ANY MEMBER STATE OF THE EEA, OR ANY OTHER JURISDICTION WHERE, OR TO ANY OTHER PERSON TO WHOM, TO DO SO MIGHT CONSTITUTE A VIOLATION OR BREACH OF ANY APPLICABLE LAW OR REGULATION. PLEASE SEE THE IMPORTANT NOTICE AT THE END OF THIS ANNOUNCEMENT.

THE COMMUNICATION OF THIS ANNOUNCEMENT AND ANY OTHER DOCUMENTS OR MATERIALS RELATING TO THE RETAIL OFFER AS A FINANCIAL PROMOTION IS ONLY BEING MADE TO, AND MAY ONLY BE ACTED UPON BY, THOSE PERSONS IN THE UNITED KINGDOM FALLING WITHIN ARTICLE 43 OF THE FINANCIAL SERVICES AND MARKETS ACT 2000 (FINANCIAL PROMOTION) ORDER 2005, AS AMENDED (WHICH INCLUDES AN EXISTING MEMBER OF PROTEOME SCIENCES PLC). ANY INVESTMENT OR INVESTMENT ACTIVITY TO WHICH THIS ANNOUNCEMENT RELATES IS AVAILABLE ONLY TO SUCH PERSONS AND WILL BE ENGAGED IN ONLY BY SUCH PERSONS. THIS ANNOUNCEMENT IS FOR INFORMATIONAL PURPOSES ONLY AND DOES NOT CONSTITUTE OR FORM PART OF ANY OFFER OR INVITATION TO SELL OR ISSUE, OR ANY SOLICITATION OF AN OFFER TO PURCHASE OR SUBSCRIBE FOR, ANY SECURITIES OF PROTEOME SCIENCES PLC.

THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION FOR THE PURPOSES OF ARTICLE 7 OF  THE MARKET ABUSE REGULATION (EU) NO. 596/2014, AS INCORPORATED INTO UK LAW BY THE EUROPEAN UNION (WITHDRAWAL) ACT 2018 ("UK MAR"). UPON THE PUBLICATION OF THIS ANNOUNCEMENT, THIS INSIDE INFORMATION IS NOW CONSIDERED TO BE IN THE PUBLIC DOMAIN.

Proteome Sciences (AIM: PRM) is pleased to announce that the Retail Offer launched on 26 January 2026 has successfully completed and closed today at 12.00 p.m.

The Retail Offer was significantly oversubscribed. Accordingly, the Company has elected to increase the scale of the Retail Offer and has raised in aggregate £132,000 through the issuance of 7,542,856 Retail Offer Shares at an issue price of 1.75 pence per Retail Offer Share.

The Retail Offer is conditional on Admission, which is expected to take place at 8:00 a.m. on 29 January 2026.

In total, the Issue has raised gross proceeds of £972,000 for the Company.

The proceeds of the Retail Offer, together with the proceeds of the Fundraise announced on 26 January 2026, will enable the Company to fund the following workstreams:

o Increasing Tandem Mass Tag ("TMT") tags plexing rate from 32X to 96X;

o Launching an innovative new range of DXT isotopic plex tags;