Role of Aldehyde Oxidase and Xanthine Oxidase in the Metabolism of Purine-Related Drugs

Purines are natural compounds that are found in all of the body's cells. They are the most widely distributed kind of N-heterocyclic substances in nature. Purines provide part of the chemical structure of some important co-enzymes and the genes of plants and animals. These compounds also participate in membrane signal transduction, translation and protein synthesis and in the form of purine nucleosides act as neurotransmitters in a variety of tissues. Purine base is also present in the structure of some important drugs such as 6-mercaptopurine (6-MP) and azathioprine (AZT). In addition, it can be found as a nucleobase in some synthetic nucleoside analogues with various pharmacological effects including antiviral and antitumor properties and numerous nucleoside analogues and their prodrugs were developed for cancer chemotherapy, treatment of patients with infections of human immunodeficiency virus (HIV) and infections caused by herpes and hepatitis viruses.