Purification and partial characterization of two proteinases from Clostridium butyricum M 55

Clostridium butyricum M55 proteinases were purified by application of a multistep procedure involving ethanol precipitation, DEAE cellulose chromatography and molecular sieving. The purified enzymes obtained were called proteinase I and proteinase II. They appeared to be homogeneous when examined by molecular sieving and polyacrylamide gel electrophoresis. The highly purified proteinases were studied for their physico-chemical properties. The influences of pH, temperature, ionic strength and amino acids composition were investigated. The effects of metal ions and of protein-structure-modifying agents support views suggesting the character of these enzymes.