Enzymologic characteristics of monoamine oxidase from liver of the skipjack tuna Katsuwonus pelamis

Substrate and inhibitory specificity of mitochondrial monoamine oxidase (MAO) from liver of skipjack tuna Katsuwonus pelamis was studied. The results of substrate—inhibitory analysis with application of chlorgilin and deprenyl might be indirect proofs of existence of one molecular MAO form in the tuna liver. Studied enzyme, as liver MAO of terrestrial mammals, deaminates tyramine, tryptamine, dopamine, serotonin, noradrenalin, benzylamine, β-phenylethylamine, N-methylhistamine and does not deaminate histamine, is not suppressed by 10 mM semicarbazide. Takrin, acriflavin, proflavin, acridine orange and pyronine G were established to be irreversible inhibitors of middle strength in respect to MAO of tuna liver. The specificity of inhibitors action upon deamination of various substrates was equal.