The Role of Citric Acid in Intermediate Metabolism in Animal Tissues

Abstract During the last decade much progress has been made in the analysis of the anaerobic fermentation of carbohydrate, but very little is so far known about the intermediate stages of the oxidative breakdown of carbohydrate. A number of reactions are known in which derivatives of carbohydrate take part and which are probably steps in the breakdown of carbohydrate; we know furthermore, from the work of S zent -G yorgyi 20) that succinic acid, fumaric acid and oxaloacetic acid play some role in the oxidation of carbohydrate, but the details of this role are still obscure. In the present paper experiments are reported which throw new light on the problem of the intermediate stages of oxidation of carbohydrate; in conjunction with the work of S zent -G yorgyi 20), S tare and B aumann 19) and M artius and K noop 13,14) the new experiments allow us to outline the principal steps of the oxidation of sugar in animal tissues.