title: [Kinetics of the inhibition of mitochondrial monoamine oxidases A and B from rat liver by 1-(indolyl-3)isopropylmethylpropargylamine].
abstract: The kinetics of inhibition of the activity of monoamine oxidases A (with 5-oxytryptamine as substrate) and B (with 2-phenylethylamine as substrate) from rat liver mitochondria by a new acetyleneamine, 1-(indolyl-3)isopropylmethylpropargylamine, was studied. It was shown that the inhibition of the both forms of monoamine oxidase results in formation of an intermediate dissociating enzyme--inhibitor complex which is further converted into an irreversibly blocked enzyme. The value of the dissociation constant, Ki, of the intermediate enzyme--inhibitor complex with 2-phenylethylamine as substrate is equal to 24 . 10(6) M, that with 5-oxytryptamine--to 0.09 . 10(-6) M. The values of the rate constants, K3, for the conversion of the enzyme--inhibitor complex into an irreversibly blocked enzyme in experiments with 2-phenylethylamine and 5-oxytryptamine were rather close, i. e. 0.06 and 0.05 min-1, respectively. The results obtained indicate that the selectivity and inhibition of the activity of monoamine oxidases A and B by propargylamine derivatives is manifested at the primary step of formation of dissociating intermediate enzyme--inhibitor complexes.
mesh_terms: D000818:Animals; D007211:Indoles / Q000494:pharmacology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D007700:Kinetics; D008930:Mitochondria, Liver / Q000201:enzymology*; D008995:Monoamine Oxidase; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology*; D051381:Rats
chemical_list: D007211:Indoles; D007527:Isoenzymes; D008996:Monoamine Oxidase Inhibitors; C039130:1-(indolyl)-3-isopropylmethylpropargylamine; D008995:Monoamine Oxidase
vernacular_title: Kinetika ingibirovaniia mitokhondrial'nykh monoaminoksidaz tipov A i B pecheni krysy 1-(indolil-3)izopropilmetilpropargilaminom.