Comparative Enzymologic Study of Catalytical Properties of Liver Monoamine Oxidases of Sturgeon Fish

摘要

We carried out the comparative study of the substrate and inhibitory specificity of liver monoamine oxidases (MAO) of the giant sturgeon Huso huso, the starred sturgeon Acipenserstellatus, the Persian sturgeon Acipenserpersicus, and the Russian sturgeon Acipenser gueldenstaedtii. Results of the substrate-inhibitor analysis with use of inhibitors chlorgilin and deprenil, as well as five specific substrates indicate homogeneity of these enzymes. All studied MAO have the several orders higher sensitivity to chlorgilin than to deprenil, with essential interspecies differences being observed. There are determined kinetic parameters of enzymatic deamination (K_M and V) of tyramine, serotonin, noradrenahn, benzylamine, p-phenylethylamine, and N-methylhistamine. All studied enzymes have been established to have the higher activity toward serotonin and noradrenahn-substrates of the MAO A form as compared with benzylamine, p-phenylethylamine, and N-methyihistamine-substrate of the mammalian MAO B form, the maximal activity being characteristic of the giant sturgeon.