MEROPS the Database of Proteolytic Enzymes, their Substrates and Inhibitors

Release 12.5

The MEROPS database is an information resource for peptidases (also termed proteases, proteinases and proteolytic enzymes) and the proteins that inhibit them. The Summary page describing a given peptidase can be reached by use of an index under its Name, MEROPS Identifier or source Organism. The Summary describes the classification and nomenclature of the peptidase and offers links to supplementary pages showing sequence identifiers, the structure if known, literature references and more.

The MEROPS database uses an hierarchical, structure-based classification of the peptidases. In this, each peptidase is assigned to a Family on the basis of statistically significant similarities in amino acid sequence, and families that are thought to be homologous are grouped together in a Clan. There is a Summary page for each family and clan, and these again have indexes. Each of the Summary pages offers links to supplementary pages.

Please use the Menu in the side-bar to navigate through the database, and consult the About pages to discover more. To reach the Inhibitors side of MEROPS click the button at the top of the sidebar.

The MEROPS website and database are run by Neil D. Rawlings, alumnus at the EMBL-European Bioinformatics Institute, Cambridge CB10 1SD, UK (

Use us and cite us!

Many authors find it useful to include data from MEROPS in their publications, and that is very much what we are here for, but please cite the appropriate publication as well as the URL when you do so. This is: Rawlings, N.D., Barrett, A.J., Thomas, P.D., Huang, X., Bateman, A. & Finn, R.D. (2018) The MEROPS database of proteolytic enzymes, their substrates and inhibitors in 2017 and a comparison with peptidases in the PANTHER database. Nucleic Acids Res 46, D624-D632.  Thank you!