Purification and Characterization of Amine Oxidase from Soybean Seedlings

A simple and rapid procedure for purification of soybean seedling amine oxidase is reported. The crude enzyme, obtained by ammonium sulfate fractionation was purified by ion-exchange chromatography on a cellulose phosphate column and batch affinity chromatography on 6-aminohexyl-Sepharose. Cyclohexylamine, a competitive inhibitor, was utilized to elute the enzyme. A homogeneous enzyme was obtained with a yield higher than 25%, the content of minor components being ≤2%. The M(r) estimated by gel filtration is 113,000 and 77,000 by sodium lauryl sulfate-polyacrylamide gel electrophotesis. The enzyme is a dimer and contains two Cu2+ ion pet molecule. Its EPR spectrum is typical of Cu2+ in a tetragonal symmetry. The enzyme oxidizes cadaverine at high rate, the specific activity being 4.3 μkat/mg. Molecular, spectroscopic, and kinetic properties of this enzyme are reported. © 1993 Academic Press, Inc.