In the MEROPS peptidase database (https://merops.sanger.ac.uk/),1 subtilases, or subtilisin-like serine proteinases, are classi’ed as the superfamily, or clan, SB of the serine proteinases. They are a highly diverse group of proteases, occurring in viruses, archaea, and eubacteria among prokaryotes, fungi, yeasts, as well as in higher eukaryotes, including plants and animals.2,3 They are classi’ed further in the MEROPS database to the S8 peptidase family (subtilisins), which is divided into two subfamilies: S8A, typi’ed by the subtilisins, and S8B, of which the yeast enzyme kexin is an example (this enzyme was the ’rst eukaryotic subtilase to be identi-’ed).4,5 The active sites of the subtilases are characterized by a catalytic triad of AspHis-Ser (DHS) residues, which they share with proteases of the chymotrypsin-like superfamily (SA), however, these catalytic residues occur in different order within the structures of members of the two superfamilies. In the subtilase superfamily the order is DHS, but it is HDS in the chymotrypsin-like enzymes. The subtilases have also been subdivided into six families, based on their sequence homology, where each family is named after a well-characterized representative enzyme belonging to the family (i.e., the subtilisin, thermitase, proteinase K, lantibiotic peptidase, kexin, and pyrolysin families).2