EFFECTS OF α-METHYL-DL-TRYPTOPHAN ON THE OXIDATION OF TRYPTOPHAN

Abstract

Alpha-Methyl-DL-tryptophan (AMT) inhibits the oxidation of DL-tryptophan by isotonic suspensions of rat liver, and the oxidation of L-tryptophan, L-tyrosine, DL-phenylalanine, and DL-methionine by cobra venom. The oxidation of L-tryptophan is accompanied by the appearance of a yellow color in the reaction mixtures. AMT also inhibits the formation of kynurenine, detected by its specific absorption at 360 m[mu] and by diazotization, from L-tryptophan. It protects the kynurenine-forming enzyme system against the inactivation which occurs in the absence of substrate. When injected into the rat, AMT, like tryptophan, causes an adaptive increase in the tryptophan peroxidase-oxidase complex. AMT is not oxidized by the liver and venom preparations used.