Regional differences for the D-amino acid oxidase-catalysed oxidation of D-methionine in chicken small intestine.

Abstract 1. 1. Enzymic oxidation of d -[1- 14 C]methionine ( d -met) to 2-keto-4-methylthiobutanoate (KMB) has been determined using 100,000 g supernatants prepared from chicken tissue homogenates. 2. 2. The small intestinal mucosa contains substantial oxidative activity towards d -met, which represents about one-half and one-tenth the hepatic and renal activity, respectively. 3. 3. KMB is poorly decarboxylated and rather transaminated to l -met. 4. 4. The specific activity for d -met oxidation in the duodenal mucosa is 1.5- and 4.0-fold that in the jejunal and ileal mucosa, respectively. 5. 5. The intestinal d -met-oxidizing activity is dramatically altered by the d -amino acid oxidase specific inhibitor benzoate.