[Isolation, crystallization and partial characterization of a cationic protease from thermoactinomyces vulgaris]

A simple method was developed for the isolation of the cationic endopeptidase from a crude extract prepared from the culture medium of Thermoactinomy ces vulgaris, consisting in chromatography on Sephadex G 75 and subsequent separation on CM-Sephadex in 50 mM Tris/HCl, pH 8, using a NaCl-gradient (0 - 0,2 M). This procedure results in a 4,2 fold increase of the elastolytic activity (substrate: N-acetyl-(L-ala)3methyl ester) of the enzyme. It moves as a single band in SDS-gel electrophoresis and crystallizes as needles up to 0,2 mm in length after standing at 5 degrees C in 50 mM Tris/HCl (pH 8,3).