PURIFICATION AND CHARACTERIZATION OF SERINE PROTEINASE OF THE GLU,ASP-SPECIFIC ENZYME FAMILY FROM THERMOACTINOMYCES SPECIES

Enzyme catalyzing hydrolysis of a substrate of Glu,Asp-specific protei nases (Z-Glu-pNA) and cleaving bond Glu 13-Ala14 in the oxidized insul in B chain was purified to homogeneity from the culture medium of Ther moactinomyces species using hydrophobic chromatography on phenyl-Sepha rose CL 4B as the key purification step. The molecular weight of the p roteinase is 23 kD. The enzyme is completely inhibited by diisopropyl fluorophosphate and is stable at pH 5-11. The pH optimum for the hydro lysis of azocasein as substrate is 8.5. The temperature optimum for pr oteolytic activity is 55 degrees C. The N-terminal sequence of the pro teinase is: -Thr-Arg-Val-Thr-Asn-Thr-Thr-Thr-Tyr-Pro-Tyr-Trp-.