The Significance of Cyanic Acid in the Urea- Tjrjxase System

The close chemical relationship between cyanic acid and urea suggests a corresponding biochemical relationship whenever urea is synthesized or decomposed in animal or vegetable tissues. For this reason the zymolysis of urea was studied by the writer (1) to see if cyanic acid could be detected among the products of the reaction, which would indicate that the enzyme decomposition of urea proceeds along the same lines as the normal decomposition of urea in solution by acids, alkalies, or heat. The data obtained led to the conclusion that cyanic acid occurs in the urea-urease system. Mack and Villars (6) also claim to have detected cyanic acid under similar conditions, although they do not ascribe any particular significance to its presence. Quite recently Sumner (ll), working with an extremely active preparation of jack bean urease, has failed to find any indication ,of the formation of cyanic acid during the zymolysis of urea. Sumner has employed the same analytical technique as the writer, and his results raise the question of the accuracy of the present methods of detecting cyanic acid in complex mixtures, and the validity of the assumption that the cyanic acid comes from the action of the enzyme on the substrate, and not from some other source.