[Catalytical properties of the liver monoamine oxidases of the commander squid Berryteuthis magister from various habitation zones].

A detailed kinetic analysis is performed of enzymatic reactions of deamination of tyramine, tryptamine, serotonin, benzylamine, beta-phenylethylamine, and histamine under action of liver monoamine oxidase (MAO) of the Commander squid Berryteuthis magister from various habitation zones in the Bering and Japan Seas. There has been revealed a substrate inhibition by high concentrations of all studied substrates, which seems to indicate mutual effect of various MAO forms present in liver of the studied squids. Analysis of kinetic parameters of enzymatic reactions of deamination of six studied substrates and the substrate-inhibitory analysis with use of two derivatives of acridine and deprenyl indicate the enzyme heterogeneity, the presence of at least two MAO forms and the absence of intraspecies differences in MAO of the Commander squids from various habitation zones. The most active was the MAO form responsible for serotonin deamination. There were obtained quantitative difference in substrate specificity and reaction ability with respect to inhibitor of proflavin for the liver MAO of the Commander and Pacific squids.