Preparation and properties of an electrophoretically homogeneous monoamine oxidase from monkey intestine

Abstract

The monoamine oxidase (monoamine:O₂ oxidoreductase (deaminating), EC 1.4.3.4)) from monkey small intestinal mitochondria has been purified by using (NH₄)₂SO₄ and Sepharose 4B fractionation, and the purified preparation was homogeneous by electrophoresis on polyacrylamide gels. The enzyme was optimally active at pH 7.6 and exhibited maximal rates with kynuramine as substrate. The enzyme was moderately inhibited by metal chelating agents and severely inhibited by p-hydroxymercuribenzoate. Several monoamine oxidase inhibitors such as Parnate, Iproniazid and Niamide showed complete inhibition at 0.1 mM, while 1-phenyl-2-isopropylhydrazine (0.1 mM) showed only 50% inhibition. There was no evidence of any multiplicity of the enzyme during fractionation.