[Functional groups of mitochondrial monoamine oxidase].
Functional groups of mitochondrial monoamine oxidase critical for monoamine oxidase activity were investigated by chemical modification of highly purified monoamine oxidase preparations from pig liver by specific inhibitors. The substrate and inhibitory properties of synthesized derivatives of beta-phenylethylamine, containing various acylating and alkylating groups in the p-position of the benzene ring, were studied. It was shown that 4-carbmethoxy-beta-phenylethylamine (I) is readily deaminated by monoamine oxidase, whereas 4-O-acetyl-beta-phenylethylamine (II) is not affected by the enzyme. 4-O-acetyl-beta-phenylethylamine (II) and 4-ethyl-O-chloroacethyl phenol (III) inhibit deamination of tyramine, 4-amino-beta-phenylethylamine, beta-phenylethylamine, 4-chloro-beta-phenylethylamine and serotonin in different degrees. The kinetic studies demonstrated that this inhibition is probably due to the acylating properties of the compounds obtained. Selectivity in inhibition may be accounted for by acylation of the group of monoamine oxidase which is located in the nearest proximity to the nucleophynoamine oxidase which is located in the nearest proximity to the nucleophylic site of monoamine oxidase active centre important for binding of tyramine. This group is neither the imidazole group of histidyl, nor the SH-group of cysteinyl residues of monoamine oxidase protein molecule. Its nature is discussed in the light of the data obtained.
D000215:Acylation; D000478:Alkylation; D000818:Animals; D001665:Binding Sites; D007700:Kinetics; D008930:Mitochondria, Liver / Q000201:enzymology*; D008995:Monoamine Oxidase / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D010627:Phenethylamines / Q000494:pharmacology; D011485:Protein Binding; D013329:Structure-Activity Relationship; D013552:Swine
D008996:Monoamine Oxidase Inhibitors; D010627:Phenethylamines; D008995:Monoamine Oxidase
O Funktsional'nykh Gruppalh Mitokhondrial'noi Monoaminoksidazy