Pyrimidine metabolism in man. I. The biosynthesis of orotic acid

Many studies of purine metabolism in man have been carried out. This is largely due to continued interest in the pathogenesis of gout and the ease of measuring serum and urinary uric acid. In contrast there have been few studies of pyrimidine metabolism in man. The major degradation products of pyrimidines are carbon dioxide and ammonia, which are lost in the general body pools. Only recently has a "pyrimidine disease, " orotic aciduria, been described (1). The role of py-rimidine nucleotides in the formation of nucleic acids and in a number of coenzyme functions emphasizes the importance of quantitative data concerning pyrimidine metabolism in man. This report describes studies of the enzymatic steps in normal blood cells leading to the formation of the first pyrimidine product, orotic acid