Retail Offer to raise up to £60,000

Proteome Sciences (AIM: PRM) is pleased to announce the launch of an offer to retail investors in the UK through BookBuild (the "Retail Offer") of up to 3,428,571 new ordinary shares of one penny each in the capital of the Company ("Retail Offer Shares") at an issue price of 1.75 pence per Retail Offer Share (the "Issue Price") to raise up to £60,000.

In addition to the Retail Offer, the Company has also completed a fundraise by way of a Placing and Subscription of new ordinary shares (the "Fundraise Shares" and together with the Retail Offer Shares, the "New Ordinary Shares") at the Issue Price (the "Fundraise" and together with the Retail Offer, the "Issue"). A separate announcement has been made regarding the Fundraise and its terms. For the avoidance of doubt, the Retail Offer is not part of the Fundraise.

The Retail Offer is conditional on the Retail Offer Shares being admitted to trading on the AIM market operated by the London Stock Exchange plc ("Admission") and, inter alia, upon completion of the Fundraise. Admission of the Retail Offer Shares is expected to take place at 8.00 a.m. on 29 January 2026.

The net proceeds from the Issue will be used 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;

o Introducing novel 'Solvent Shift' chemoproteomic workflows;

o Concluding a DXT licence;

o Expanding staff and mass spectrometry ("MS") capacity in San Diego to meet demand; and

o Additional working capital.

Expected Timetable in relation to the Retail Offer

Any changes to the expected timetable set out above will be notified by the Company through a Regulatory Information Service. References to times are to London, UK times unless otherwise stated.

Dealing Codes

Retail Offer

The Company values its retail shareholder base. Given the support of retail shareholders, the Company believes that it is appropriate to provide its retail shareholders in the United Kingdom the opportunity to participate in the Retail Offer. The Company is therefore making the Retail Offer available in the United Kingdom through the financial intermediaries which will be listed, subject to certain access restrictions, on the following website: https://www.bookbuild.live/deals/JQKP41/authorised-intermediaries

SP Angel Corporate Finance LLP will be acting as retail offer coordinator in relation to this Retail Offer (the "Retail Offer Coordinator").

The Retail Offer will be open to eligible investors in the United Kingdom from 7:30 a.m. on 26 January 2026. The Retail Offer is expected to close at 12:00 p.m. on 28 January 2026. Investors should note that financial intermediaries may have earlier closing times. The Retail Offer may close early if it is oversubscribed.

The Retail Offer, which is the subject of this announcement, is and will, at all times, only be made to, directed at and may only be acted upon by those persons who are, shareholders in the Company. To be eligible to participate in the Retail Offer, applicants must meet the following criteria before they can submit an order for Retail Offer Shares: (i) be a customer of one of the participating intermediaries listed on the above website; (ii) be resident in the United Kingdom; and (iii) be a shareholder in the Company (which may include individuals aged 18 years or over, companies and other bodies corporate, partnerships, trusts, associations and other unincorporated organisations and includes persons who hold their shares in the Company directly or indirectly through a participating intermediary). For the avoidance of doubt, persons who only hold CFDs, Spreadbets and/or similar derivative instruments in relation to shares in the Company are not eligible to participate in the Retail Offer.

The Company and the Retail Offer Coordinator reserves the right to scale back any order at its discretion. The Company reserves the right to reject any application for subscription under the Retail Offer without giving any reason for such rejection.

There is a minimum subscription of £100.00 per investor under the terms of the Retail Offer which is open to investors in the United Kingdom subscribing via the intermediaries which will be listed, subject to certain access restrictions, on the following website: https://www.bookbuild.live/deals/JQKP41/authorised-intermediaries

The Company's LEI is 213800Q62ICXANKU2986.

UK Product Governance Requirements

EU Product Governance Requirements