Uronic acids
Uronic acids are carboxylic acids that are formally formed by oxidation of the primary hydroxyl group of monosaccharides (−CH 2 −OH) to the carboxy group (−COOH). They belong to the sugar acids . The nomenclature is based on the underlying monosaccharide. The uronic acid of glucose is called glucuronic acid , regardless of whether it is open-chain or with a ring structure as pyranose or furanose . The salts of uronic acids are called uronates , e.g. B. Glucuronate.
Physiological importance
Uronic acids play an important physiological role. Metabolites become sufficiently hydrophilic through salt formation with glucuronic acids to be able to excrete them via the kidneys . Furthermore, uronic acids occur in structural elements such as glycosaminoglycans and proteoglycans .
biogenesis
The uronic acid pathway is an alternative way to oxidize glucose and produce activated glucuronate , UDP -glucuronate. A production of energy in the form of ATP is not possible in this way.
Of glucose-6-phosphate is produced, catalyzed by the enzyme phosphoglucomutase , first glucose-phosphate 1 . This is now activated by UDP and catalytically oxidized to UDP-glucuronic acid while consuming NAD +. The activated glucuronic acid is a precursor for a number of other molecules such as bilirubin , steroids and a number of other, also pharmacologically relevant molecules.
See also
Individual evidence
- ↑ Peter Nuhn : Naturstoffchemie. Microbial, vegetable and animal natural substances. 2nd revised and expanded edition. S. Hirzel, Stuttgart 1990, ISBN 3-7776-0473-9 , pp. 181-183.