Health depends largely on the maintenance of the enzyme systems within the cells of the body. Accordingly, substances in foods which serve as structural units of certain of these enzymes have a peculiar importance in the animal economy. A number of the vitamins function as essential components of enzyme systems concerned with processes of oxidation. Thus thiamine in the form of a pyrophosphoric acid ester is the enzyme cocarboxylase, important in the oxidation of pyruvic acid, an intermediate in carbohydrate metabolism. In a somewhat similar manner riboflavin is present in the yellow oxidation ferment of Warburg, and nicotinic acid functions as coenzyme in still another enzyme system. Now it appears from a recent detailed report by Keilin and Mann1 that zinc, one of the trace elements in nutrition, is a constant ingredient of purified preparations of carbonic anhydrase.
Carbonic anhydrase has been known since 1933, when Meldrum and Roughton