A Cysteine-Activated Proteinase of Clostridium Histolyticum

Discussion and Summary A cysteine-activated proteolytic enzyme present in culture filtrates of Cl. histolyticum has been purified by fractionation in methanol-water mixtures under controlled conditions of pH, ionic strength, protein concentration and temperature and further purified by differential centrifugation, lyophilization and ammonium sulfate fractionation. The purified enzyme exhibits almost none of the lethal, necrotizing, and muscle digesting properties of the parent filtrates and only a small fraction of the collagenase activity originally present. These results clearly demonstrate that the lethal and necrotizing toxin are distinct from the cysteine-activated proteinase and provide independent confirmation of the work of Oakley and Warrack (12) whose conclusions were based entirely on immunological methods. The cysteine-activated proteinase would appear, therefore, to be only of secondary importance in Cl. histolyticum infections. The lethal and necrotizing toxin remains biochemically unidentified and requires further investigation.