[Substrate specificity of monoamine oxidase in rat liver mitochondria using an air-gap electrode].

The dependency of initial rates of tyramine, tryptamine, serotonin and benzylamine reactions of deamination catalyzed by rat liver monoamine oxidase from its concentrations was studied potentiometrically using an air-gap electrode. The kinetic deamination parameters, i.e. Michaelis constants an maximum velocities, were determined at pH values of 7.6 and 9.0. The inhibition of tyramine deamination at high concentrations of the latter was found for a pH value of 9.0 and the activation of serotonin deamination by its high concentrations for pH values of 7.6 and 9.0. The effects studied may be interpreted in terms of the allosteric nature of MAO.