Alkaline proteinase E of Streptomyces griseus K-1

A fifth and new DFP-sensitive alkaline proteinase E, with strong esterase activity toward Ac-(Ala)3-OMe was found in pronase, a protease mixture from St. griseus K-1. Proteinase E was shown to be different from the elastase [EC 3.4.21.11]-like enzyme or subtilisin [EC 3.4.21.14]like enzyme, and alkaline proteinase A, B, and C in pronase. Proteinase E was purified to a state appearing homogeneous on polyacrylamide gel electrophoresis. Its molecular weight was estimated as 26,600 by gel filtration. It was unstable below pH 5.6. Studies on its actions on acyl-amino acid esters showed that it hydrolyzed the ester bonds of esters of tryptophan, tyrosine, phenylalanine, leucine, and alanine in decreasing order of ease.