Purification and Properties of Aminopeptidase from Flavobacterium sp.
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An aminopeptidaase of Flavobacterium sp. K172 was purified to homogeneity and its physicochemical and enzymatic characteristics were studied. The molecular weight of the enzyme was determined to be 80,000 by Sephadex G-200 column chromatography and that of its subunit was estimated at 43,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis.This aminopeptidase was a zinc-enzyme in which Zn^<2+> could be replaced by Co^<2+>.The enzyme was inhibited by 2.2μM ethylenediaminetetraacetate, and 0.15 mM o-phenanthroline, and the enzyme inactivated by o-phenanthroline was reactivated by the addition of either zinc chloride or cobaltous chloride.The enzyme hydrolyzed a variety of peptides with free amino termini. A strong substrate specificity for the amino terminal amino acid of the peptides was not observed.In the hydrolysis of oligopeptides, the dipeptide was hydrolyzed more slowly than other oligopeptides.