Uridine 5'-diphospho-glucuronosyltransferase (UDP-glucuronosyltransferase, UGT) is a naturally-occurring enzyme () that catalyzes the glucuronidation reaction. This reaction involves the addition of sugars to fat-soluble molecules and is an important step in the body's elimination of foreign substances (such as drugs) as well as endogenous substances (including toxins). UGP is present in humans, other animals, plants, and bacteria.

The glucuronidation reaction consists of the transfer of the glucuronosyl group from uridine 5'-diphospho-glucuronic acid (UDPGA) to substrate molecules that contain oxygen, nitrogen, sulfur or carboxyl functional groups. The resulting glucuronide is more polar, more water soluble, less toxic, and is more easily excreted than the substrate molecule. The product is eliminated from the body by the kidneys.

Alternative names:

• glucuronyltransferase

Diseases

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A deficiency of glucuronosyltransferase is thought to be the cause of Gilbert's syndrome, which is characterized by hyperbilirubinemia.

It is also associated with Crigler-Najjar syndrome.

EC 2.4.1