Human Pyrimidine Metabolism

Abstract

Studies of pyrimidine metabolism in man have assumed interest in recent years with the recognition of specific alterations in their synthesis and excretion in certain diseases. Further, several pyrimidine antimetabolites have been introduced into cancer chemotherapy, and the metabolic alterations produced by some of these, 6-azauridine, has been a subject of physiological and biochemical interest. The pyrimidine ring is a common component of biologically active substances. It occurs in a variety of therapeutic compounds such as xanthine oxidase inhibitors, antimetabolites, antithyroid substances, sedatives, and vitamins. Among natural substances, pyrimidines occur most abundantly in the nucleic acids. Ribonucleic acids contain large amounts of uracil and cytosine derivatives (Fig 1), and deoxyribonucleic acid (DNA) contains cytosine and thymine derivatives (Fig 1). Pyrimidines also appear in a variety of acid-soluble phosphorylated cofactors, such as uridine diphosphoglucose, which play a central role in carbohydrate and lipid metabolism. <h3>Normal Pyrimidine Metabolism</h3> The pathway of pyrimidine