There are 2415 different peptidases recognized in the MEROPS database (excluding hypothetical peptidases from model organisms). Substrate cleavages have been collected for 1086 peptidases (45%); for the remainder any cleavage positions in substrates are either unknown or have not yet been found in the literature. Only 312 peptidases have had ten or more cleavages collected, and it is only these for which there is enough data for further analysis. The total number of cleavages for these 312 