Interaction of Primary Amines with a Mixed-Function Amine Oxidase Isolated from Pig Liver Microsomes

Abstract

1. This work describes the interaction of a variety of primary amines with a purified microsomal mixed-function oxidase that catalyzes the N-oxidation of sec.- and tert.-amines. 2. Most of the primary amines tested are not catalytically oxidized by this isolated microsomal oxidase. Only 2,4-dichloro-6-phenylphenoxyethylamine (DPEA), 1-naphthylamine, and 2-naphthylamine appear to be oxidized at measurable rates. 3. 2-Naphthylamine is enzymically oxidized at a considerably faster rate than 1 -naphthylamine. 4. Primary alkylamines, while not enzymically oxidized by this enzyme, interact with a regulatory site on the oxidase and enhance the rate of N-oxidation of sec.- and tert.-amines catalyzed by this NADPH- and oxygen-dependent amine oxidase. 5. With microsomal-catalyzed oxidations, primary amines that enhance the rate of N-oxidation also inhibit the rate of oxidative N-demethylation.