glucuronyl

Glucuronyl refers to a glucuronyl residue, derived from glucuronic acid, that occurs in carbohydrates, glycosaminoglycans, and detoxification pathways. Glucuronic acid is a hexuronic sugar formed by oxidation of glucose; in physiological conditions its anionic form is commonly described as glucuronyl.

In glycans, glucuronyl residues are common components of glycosaminoglycans such as hyaluronan, heparan sulfate, heparin, and chondroitin sulfate, where they typically alternate with hexosamines to form repeating disaccharide units. The glucuronyl unit is usually linked through the anomeric carbon of the sugar to the next sugar, contributing to the structure and properties of the extracellular matrix and to cellular signaling.

Biotransformation of xenobiotics and many endogenous compounds often proceeds via glucuronidation. UDP-glucuronosyltransferases transfer glucuronic acid from UDP-glucuronic acid to substrates, forming glucuronides that are more water-soluble and easier to excrete. This reaction is a major phase II detoxification pathway in the liver and other tissues, producing glucuronyl conjugates that can be eliminated in urine or bile.

Biosynthetically, the glucuronyl unit is generated from UDP-glucose through oxidation to UDP-glucuronic acid, catalyzed by UDP-glucose dehydrogenase, providing the donor for glucuronidation and glycan assembly. The term glucuronyl is widely used in enzymology, glycoscience, and pharmacology to designate the glucuronyl moiety involved in glycan structure or in conjugation reactions.