MEROPS is a freely accessible database containing information on all known peptidases (proteases ) and their inhibitors. In particular, it is the source of the MEROPS classification of these biomolecules.

The MEROPS team is part of the Sanger Institute of the Wellcome Trust and is financially supported by the Medical Research Council (UK ).

The short form of the peptidase classification has the form X12.345 where X is chosen as the capital letter of S, C, T, A, G, M, or U, and the data means clan or family number. Clans are groups of families, which in turn arise due to similarities in the amino acid sequence.