A substantially pure subtilisin modified by a substitution of at least one amino acid at a residue position with a different naturally occurring amino acid, said residue position being selected from the group of equivalent amino acid residues of subtilisin naturally produced by Bacillus amyloliquefaciens consisting of His67, Ile107, Leu135, Gly97, Ala98, Asp99, Gly100, Ser101, Gly102, Gln103, Leu126, Gly127, Gly128, Pro129, Lys213, Tyr214, Gly215, Gly153, Asn154, Gly157, Thr158, Ser159, Gly160, Ser161, Ser162, Ser163, Thr164, Val165, Tyr167, Pro168, Lys170, Tyr171 and Pro172 wherein said modified subtilisin has altered substrate specificity as compared to the same subtilisin having the amino acid naturally occurring at the residue position, wherein the subtilisin which is modified is selected from the group consisting of subtilisins derived from procaryotes, yeast and fungi.