Purification and Some Properties of Tea Leaf Amine Oxidase

抄録

Tea leaf amine oxidase was purified by salting out and various column chromatographies. The molecular weight was estimated to be 162, 000 daltons by gel filtration on a Sephadex G-200 column. This enzyme was determinated to be a dimer of which the molecular weight was found to be 81, 000 daltons by SDS gel electrophoresis. The optimum pH for ethylamine oxidation by this enzyme was 7.0. The enzyme was stable up to 60°C From the results of a inhibition study with chelating agents, the enzyme was found to contain copper in the cupric state. Carbonyl reagents such as semicarbazide, hydroxylamine and hydrazine strongly inhibited the activity. The enzyme oxidized alkylamines, ethanolamine and benzylamine rapidly, and also oxidized tyramine, histamine and other diamines slowly. The Km value for ethylamine was 8.8 × 10^-5M. Polyamines, secondary amines and tertiary amines were not oxidized.