Glucuronidation

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Glucuronidation describes the process of excretion of non-polar substances via the liver and kidneys by binding to glucuronic acid - a uronic acid that is formed from glucose by double oxidation at carbon atom 6 (C 6 ) . The glucuronidation takes place in the endoplasmic reticulum of hepatocytes instead.

Toxins and drugs as well as the body's own substances such as steroid hormones or bilirubin become glucuronides by binding to glucuronic acid. These are much more hydrophilic than the original substance to be excreted and can therefore be excreted better through the kidneys.

The combination of these substances with glucuronic acid is a UTP requires -dependent activation reaction, which by the enzyme UDP-glucuronosyltransferase , a glycosyltransferase , catalyzed is. The resulting product of this reaction is UDP-glucuronic acid , the activated form of glucuronic acid. Without this activation of the glucuronic acid, subsequent steps would be endergonic and therefore practically impossible in the cells. Finally, by splitting off the UDP at carbon atom 1 (C 1 ) of the UDP-glucuronic acid, one of the substrates mentioned can be linked to the glucuronic acid at C 1 via a glycosidic bond .

literature

  • Florian Horn, Isabelle Moc, Nadine Schneider, Christian Grillhösl, Silke Berghold, Gerd Lindenmeier: Human biochemistry . Thieme, Stuttgart 2005, ISBN 3-13-130883-4 .
  • Roche Lexicon Medicine , 5th edition, Urban & Fischer, Munich 2003.

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