Isolation and properties of leucine aminopeptidase from Aspergillus oryzae]

Homogenious leucine aminopeptidase is purified from "oryzine"--mixture of enzymes produced by surface culture of Asperigillus oryzae using treatment with activated characoal, followed by DEAE-cellulose and hydroxylapatite chromatographies, Biogel P-100 gel-filtration and polyacrylamide-gel electrophoresis. The enzyme has pH optimum 9.0 and the molecular weight 37500 as estimated by gil-filtration through Sephadex G-100 (superfine) and SDS-polyacrylamide gel electrophoresis. Leucine aminopeptidase from Asp. oryzae has a broad substrate specificity, therefore, cleaving with the highest rate the peptides carrying N-terminal leucine. The enzyme is completely inhibited with EDTA and beta-mercaptoethanol, and it is a metalloenzyme.