Action and Specificity of a Streptomyces Alkalophilic Proteinase

Action of the crystalline alkalophilic proteinase of a Streptomyces sp. which was active at pH values around 13, was investigated. The enzyme attacked various keratinous proteins such as wool, hair, feather etc., dissolving them with hydrolysis degrees from 2 to 6%, and the degradation of several keratins was observed under a microscope and scanning electron-microscope. Specificity of the enzyme was also studied using oxidized insulin B-chain. The enzyme cleaved most easily the peptide linkages between -Ser · His-, -Leu · Val-, -Phe · Tyr- and -Lys · Ala-, though it split several other sites of oxidized insulin B-chain, too, indicating that the action pattern of the proteinase is distinguished from those of alkaline proteinases so far reported.