[SH-dependent aminopeptidase from bovine kidney. Isolation, physico-chemical properties and substrate specificity]

The SH-dependent aminopeptidase was isolated from bovine kidney and purified 800-fold. The enzyme has a pH optimum of 7.0 and pI of 5.5 and is activated by dithiothreitol and inhibited by p-chloromercurybenzoate. The enzyme has a molecular weight of 56000 and is represented by four polypeptide chains with m. w. of 14000. Aminopeptidase hydrolyzes beta-naphthylamides of arginine, alanine, leucine and proline and peptides with free N-terminal neutral and basic amino acid residues having L-configuration as well as angiotensin III. The enzyme does not split proteins, angiotensins I and II, B-chains of insulin and peptides with a blocked N-terminal amino group and peptides with proline as a second amino acid from the NH2-end.