The catalytic behaviour of monoamine oxidase

Evidence concerning the kinetic mechanism of the reaction catalyzed by monoamine oxidase is reviewed with particular reference to the possibility that the double-displacement mechanism followed by other substrates is not operative with benzylamine. The requirement for only one of the two products of the first half-reaction to be released in a double-displacement mechanism indicates that the available evidence does not exclude such a mechanism with benzylamine as the substrate. Cases in which substrates also act as time-dependent inhibitors are considered. The mechanism that can describe the inhibition and product formation is similar for the compounds MD 780236 and MPTP whereas that describing the effects of high concentrations of 2-phenethylamine is best described by a scheme involving inhibition occurring via an abortive complex.