Biochemical characteristics of liver and brain monoamine oxidase from pacu

Monoamine oxidase (MAO) activity in the liver and brain of the pacu, Piarac tus mesopotamicus was determined using a fluorescence assay with kynuramine as substrate. Apparent Michaelis constant values (20.33 muM for liver and 25.85 muM for brain) were similar in these tissues, but in terms of tissue protein MAO activity from liver was 4.5 times higher than from brain. The g reater inhibitory effects of clorgyline than of deprenyl on MAO activity fr om liver and brain of this species suggest that pacu's MAO is a type A-like enzyme. (C) 2001 The Fisheries Society of the British Isles.