Abstract
The purification of protease, produced by Staphylococcus hyicus subsp. hyicus strain No.111, was performed by successive precipitations with ammonium sulfate and cold acetone, chromatography on DEAE-cellulose and gel filtration on Sephadex G-75. By the procedure, the protease was purified 474.1-fold, and its recovery rate was 34.9%. The purity of the preparation was demonstrated by polyacrylamide gel electrophoresis, the immunodiffusion test and immunoelectrophoresis. The protease was most active at a neutral value of pH. The protease activity was inhibited by the presence of Cu, Zn, Ag, Fe, or Hg ions, but was slightly stimulated by Ca ion. No protease was stimulated by the reducing agents such as cysteine, 2-mercaptoethanol and sodium thioglycolate, and it was strongly inhibited by the addition of EDTA. The molecular weight of the purified protease was estimated to be 32, 000 by SDS-polyacrylamide gel electrophoresis.
