Glukuronid

Glukuronid, or glucuronide in English, refers to a molecule that has been conjugated with glucuronic acid through the process of glucuronidation. This reaction attaches the glucuronyl group to a substrate, often via an O-, N-, or S-linkage, forming glucuronides that are more water-soluble than their aglycones.

Glucuronidation is a major phase II metabolic pathway that occurs chiefly in the liver, but also in the intestines, kidneys, and other tissues. The reaction is catalyzed by UDP-glucuronosyltransferases (UGTs) and uses UDP-glucuronic acid as the activated sugar donor. By adding the glucuronyl moiety, glucuronidation increases polarity and facilitates elimination of endogenous compounds such as bilirubin, hormones, and bile acids, as well as xenobiotics and drugs.

Most glucuronides are excreted via the urine or bile. In some cases, glucuronides released into the intestine can be hydrolyzed by bacterial beta-glucuronidases, releasing the aglycone for reabsorption in a process known as enterohepatic recirculation.

Examples of glucuronides include bilirubin diglucuronide, and drug metabolites such as morphine-3-glucuronide and acetaminophen glucuronide. Pharmacogenetic and drug interaction factors can influence glucuronidation; for instance, reduced UGT activity can contribute to disorders like Gilbert syndrome, and inhibitors or inducers of UGTs can affect drug clearance.

Glukuronidation is widely used in pharmacology and toxicology to describe how substances are rendered more water-soluble for elimination, shaping both therapeutic efficacy and toxicity profiles.