COMPARISON OF SPECIFICITIES OF VARIOUS SERINE PROTEINASES FROM MICROORGANISMS

A comparative study was made on the specificities of five serine proteinases from Bacillus subtilis, Streptomyces fradiae, and Aspergillus oryzae using various synthetic substrates and oxidized insulin B chain. They preferentially hydrolyzed the linkages containing the carboxyl group of l-tyrosine, l-phenylalanine, l-leucine, etc., and thus possessed specificities similar to that of chymotrypsin. These enzymes further exhibited more or less activities against benzoyl l-arginine ethyl ester and acetyl l-lysine methyl ester which are specific substrates for trypsin. The five serine enzymes which were obtained from different microorganisms were therefore considered to belong to the same type in respect to their specificities, although some small differences were observed among them. © 1969.