The data collected are non-redundant. If more than one paper reports the cleavage at the same position in the same protein by the same peptidase, then only data from the paper published first is retained. If several peptidases cleave the same protein in the same position, each is considered a different cleavage event and each is entered. There is no attempt to map cleavages to isoforms of a protein, unless different isoforms were used by the original researchers. Synthetic substrates that differ only in leader (for example benzyloxycarbonyl, succinyl or tosyl) or reporter groups (for example aminomethylcoumarin, naphthylamide or nitroanilide) are considered different cleavages even if all are performed by the same peptidase.