Comparative study of catalytic properties of mink and rat liver monoamine oxidase

Abstract

Comparative substrate-inhibitor analysis of catalytic properties of monoamine oxidase (MAO) of liver mitochondrial of the American mink Mustela vison Schreber and of liver of Wistar rat has been performed. It has been established that MAO of mink, like MAO of rat, has properties of classic mammalian MAO: it deaminates tyramine, tryptamine, serotonin, benzilamine, beta-phenylethylamine and does not deaminate histamine as well as does not have sensitivity to semicarbazide. Study of kinetics of monoamine oxidase deamination has allowed revealing both qualitative and quantitative differences between these enzymes. Specificity of action on MAO, form A, of four irreversible inhibitors--acridine derivative--has been established; the specificity for the mink liver MAO was several times higher than for the rat liver MAO. It is suggested that liver MAO of both species of the studied animals has several isoenzyme forms or several centers of substrate binding.