Enzymic and chemical properties of an endopeptidase from the larva of the hornet Vespa crabro

Abstract

An endopeptidase from the larvae of the hornet V. crabro was purified to homogeneity. The enzyme has been characterized with respect to MW, amino acid composition, and amino- and carboxyl-terminal sequences. The catalytic properties of the hornet protease are similar to those of bovine chymotrypsin with respect to inactivation by phenylmethanesulfonyl fluoride and carbobenzoxyphenylalanine chloro ketone and preferential peptide bond cleavage at aromatic amino acid residues. In contrast to bovine chymotrypsin, the hornet protease is not inhibited by the basic pancreatic Kunitz inhibitor, soybean inhibitor, or chicken ovomucoid. The MW, as determined by several independent methods, was 14,500. The protease is a single-chain protein containing 2 disulfide bonds. The terminal sequences are: NH2-Ile-Val-Gly-Gly-Ile-Asp.....Gly-Lys-Tyr-Pro-Tyr-Gln-Val-Ser-Leu-Arg-COOH.