Clostripain (Endoproteinase-Arg-C)

Clostripain is a sulfhydryl proteinase associated with collagenase and isolated from Clostridium histolyticum. It is highly specific for the carboxyl peptide bond of arginine.

Characteristics of the Enzyme from Clostridium histolyticum

Molecular Weight: Gilles et al. (1979) indicate it to be composed of two chains with relative molecular masses of 45,000 and 12,500.

Composition: The amino acid composition is described by Mitchell and Harrington (1968). Studies on the active site are reported by Porter et al. (1971).

Optimum pH: pH 7.4-7.8 (activity against a-benzoyl-arginine ethyl ester).

Isoelectric point: 4.8-4.9 (8°C.)

Inhibitors: Oxidizing agents and sulfhydryl reactants; also Co²⁺, Cu²⁺, Cd²⁺, and heavy metal ions. Citrate, borate, and Tris anions partially inhibit. TLCK reacts with active site. (Porter, et al., 1971).

Activators: Sulfhydryl requirement -- dithiothreitol, cysteine, or other reducing agents. Calcium ion is essential.