Isolation and characterization of an extracellular protease of Actinomyces pyogenes

An extracellular protease from Actinomyces pyogenes ATCC 19411 could be isolated by ion exchange chromatography with DEAE cellulose and high performance gel filtration (FPLC) on Superose 12 prep grade. The purified enzyme had a relative molecular mass of approximately 37,000 Dalton, a pH optimum at 7.5, a temperature optimum at 50 degrees C, and a Km value of 2.2 mg/ml with azocasein as substrate. The enzyme activity was clearly inhibited by PMSF, EDTA, the metal ion Zn++ and only weakly by Cd++ and Co++. Preparative isoelectric focussing of the culture supernatant from A. pyogenes ATCC 19411 revealed one major point with protease activity at pH 5.2.