The specificity of the Bacillus amyloliquefaciens intracellular serine protease: A comparison with the specificity of secretory subtilisins

Abstract 1. 1. Intracellular serine protease split a single peptide bond Ala 20 -Ser 21 of the trypsin-insensitive native pancreatic ribonuclease A, thus forming its trypsin-sensitive derivative, ribonuclease S. 2. 2. The enzyme split a single peptide bond Leu 15 -Tyr 16 in the B-chain of oxidized bovine insulin and preferred Leu in a P 1 position of the p -nitroanilide peptide substrates. 3. 3. The cleavage specificity of the enzyme lies within the limits of the subtilisin specificity, being somewhat more restricted.