Inhibition of copper-containing amine oxidase by oximes.

Abstract

The inhibitory effects of twelve oxime compounds on the activity of bovine serum monoamine oxidase (copper-containing amine oxidase, E.C. 1.4.3.6) were assayed in vitro. The most potent inhibitor among the compounds examined was 2-butanone oxime, of which the 50% inhibiting concentration in the reaction mixture was 7×10-6 M. Acetone oxime, acetoaldehyde oxime, salicylaldehyde oxime and formamide oxime were less potent inhibitors, while 2, 3-butanedione monooxime, 2, 3-butanedione dioxime, D-camphor oxime, α-furil dioxime, pyridine-2-aldehyde oxime, pyridine-4-aldehyde oxime, syn-2-pyridialdehyde oxime and di-2-pyridiketone oxime exhibited virtually no inhibitory effect on the enzyme activity. The type ofinhibition by 2-butanone oxime was non-competitive, and the inhibitor constant and Km value with respect to allylamine as the substrate were estimated graphically to be 6.7×10-6 and 3.9×10-4 M, respectively.