Clostripain (EC220.127.116.11, clostridiopeptidase B, clostridium histolyticum proteinase B, alpha-clostridipain, clostridiopeptidase, Endoproteinase Arg-C) is a proteinase that cleaves proteins on the carboxyl peptide bond of arginine. It was isolated from Clostridium histolyticum. The optimum pH of the enzyme is 7.4~7.8.
^Gilles, A.-M., Imhoff, J.-M. and Keil, B. (1979). "α-Clostripain. Chemical characterization, activity, and thiol content of the highly active form of clostripain". J. Biol. Chem.254: 1462–1468. PMID762145.