Isolation of Bacteriolytic Endopeptidase from a Strain of Cytophaga and Its Application to Preparation of Hydrosoluble Polysaccharide Peptide from Staphylococcus epidermidis Peptidoglycan

Abstract

A microorganism, which produced a potently bacteriolytic endopeptidase, was isolated from soil and classified taxonomically as Cytophaga sp. B-30. This enzyme was purified 740-fold from the culture broth by fractionations with ammonium sulfate and acetone, column chromatographies on CM-cellulose and hydroxyapatite twice, and gel filtration on Sephadex G-75. It was found to be homogeneous on PAGE and SDS-PAGE. The molecular weight and isoelectric point of this enzyme were estimated to be 9,000 daltons and pH 9.5, respectively, and the optimal pH for its activity was 9.5. The enzyme acivity was completely inhibited by Mn^{+ +}, Zn^{+ +}, Cu^{+ +}, Hg^{+ +}, 2-mercaptoethanol and 2,3-dimercapto-l-propanol but markedly stimulated by EDTA, potassium oxalete and sodium pyrophosphate at the concentration of 1 mM. This enzyme catalyzed both cell wall lysis and proteolysis. A polysaccharide peptide of long chain length was isolated from a digest of Staphylococcus epidermidis peptidoglycan with this enzyme.