The role of serine and acetate in uric acid formation.

In man the nitrogen in position 7 is derived from glycine (3). Similar mechanisms are involved in the formation of the nucleic acid guanine in yeast (4) and hypoxanthine in pigeon liver homogenates (5). The earlier demonstration that L-serine is extensively converted to glycine (6) and, presumably, a 1 carbon intermediate provides ground for belief that the P-carbon atom of serine may be a precursor of the ureide carbon atoms of uric acid. Formate could enter these positions through condensation with glycine to form serine (7), which would act as a distributor or carrier of formate in the organism. In order to test this scheme serine labeled with N15 and with Cl4 in the P-carbon atom was synthesized and resolved. This report deals with the utilization of Dand n-serine for uric acid formation in the pigeon, and a reinvestigation of the utilization of acetate. Positions .%?, 7, and 8-A complete summary of the data obtained with