A Sensitive Fluorometric Assay of Human Platelet Monoamine Oxidase and Its Application to Assessment of Monoamine Oxidase Inhibitor

An assay method of human platelet monoamine oxidase is presented based on the fluorometric determination of benzaldehyde formed from the substrate benzylamine under the optimal enzyme reaction conditions by the 1, 2-diaminonaphthalene method. This method is very sensitive and permits the assay even with 50 μg of platelet protein. The method was successfully applied to the assessment of inhibitory effect of monoamine oxidase inhibitors (tranylcypromine, pargyline, iproniazid, nialamide, isoniazid and cuprizone).