[Kinetic properties of monoamine oxidase isoenzymes from the bovine brain].

Multiple forms of monoamine oxidase (MAO I, IIa, IIb, III) from bovine brain, separated by means of affinity chromatography on AH-Sepharose 4B, were dissimilar in kinetics of deamination of serotonin and beta-phenylethylamine used as substrates of the MAO of A and B types. MAO-I catalyzed the deamination of beta-phenyl ethylamine and serotonin. Km and Vmax values could not be calculated for MAO-IIa since the rate of enzymatic reactions was characterized by a complicated dependence on concentration of serotonin in a sample. MAO-IIb catalyzed also the deamination of both AMO substrates.