| Summary: | An aminopeptidase was isolated from a soluble fraction of Alaska pollack roe in the presence of 2-mercaptoethanol by fractionation with ammonium sulfate and column chromatography on DEAE-cellulose, hydroxyapatite, and Sephadex G-200. The molecular weight of the enzyme was estimated to be 125,000 and 105,000 by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, respectively. The pH optimum and temperature optimum were 7.2 and 35°C, respectively. The purified enzyme hydrolyzed various α-aminoacyl β-naphthylamides and cleaved L-Ala-β-naphthylamide most rapidly. Both a sulfhydryl group and a divalent metal ion are essential for activity; however, the enzyme was inhibited when incubated with divalent metal ions. Puromycin, chelating agents, and thiol reagents were effective inhibitors. The enzyme was also inhibited by L-amino acids, in particular glutamic acid. Thus, the Alaska pollack roe aminopeptidase resembles soluble alanyl aminopeptidase [EC 3.4.11.14].
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