UDPglükuronsav

UDP-glucuronic acid, often abbreviated as UDPGA, is a vital nucleotide sugar that plays a central role in cellular metabolism. It is a substrate for glucuronidation, a major metabolic pathway in many organisms, including humans. In this process, UDPGA serves as a glucuronosyl donor, transferring a glucuronic acid moiety to a wide range of acceptor molecules. These acceptors include drugs, toxins, hormones, and bilirubin. The addition of glucuronic acid, known as conjugation, typically increases the water solubility of these compounds, facilitating their excretion from the body.

UDPGA is synthesized primarily in the liver from glucose. The pathway involves the conversion of glucose-6-phosphate to glucose-1-phosphate, followed by activation with uridine triphosphate (UTP) to form UDP-glucose. UDP-glucose is then oxidized to UDPGA by UDP-glucose dehydrogenase. This enzyme requires NAD+ as a cofactor.

The glucuronidation reaction is catalyzed by UDP-glucuronosyltransferases (UGTs), a superfamily of enzymes. These enzymes are found in various tissues, with the highest concentrations in the liver, kidneys, and intestines. The conjugation process is crucial for detoxification, as it renders many potentially harmful substances more easily eliminated by the body. Furthermore, glucuronidation is involved in the metabolism of endogenous compounds like steroid hormones and thyroid hormones, influencing their activity and elimination. Defects in UDPGA synthesis or UGT activity can lead to various metabolic disorders and altered drug responses.