1. 1. Carbohydrate oxidase, an enzyme obtained from the mycelium of the Basidiomycete Polyporus obtusus, has been shown to catalyze the oxidation of several carbohydrates at the second carbon atom to yield 2-keto products. The reactions catalyzed are as follows: 1.1. a. d-glucopyranose + O2 → d-glucosone + H2O2 1.2. b. d-xylopyranose + O2 → d-xylosone + H2O2 1.3. c. l-sorbose + O2 → 5-keto-d-fructose + H2O2 1.4. d. δ-d-gluconolactone + O2 → 2-keto-d-gluconic acid + d-araboascorbic acid + H2O2 2. 2. Other carbohydrates were tested and found not to be substrates. The structural requirements for substrate reactivity were studied. 3. 3. The oxidation of δ-gluconolactone to araboascorbic acid was shown to be inhibited by d-glucose, d-xylose and l-sorbose. 4. 4. The specificity of carbohydrate oxidase was compared with that of enzymes reported to occur in other microorganisms. © 1968.
