title: [UDP-glucuronyltransferases, proteins of endoplasmic reticulum--structure and mechanism of action].
abstract: UDP-glucuronyltranferase isoenzymes, UGTs, are responsible in mammals for conjugation of glucuronic acid generated by UDPGA with aglicon. UDPGA is bound to the appropriate group of I phase metabolite or, occasionally, to the native compound. As a result, the aglicon polarity increases, excreatable product in human urine is formed and, in turn, toxic effects are reduced. UGT protein structure consists of 2 domens. N-terminal catalyses of aglicon binding, whereas, C-terminal controls the addition of uridine-5'-diphosphoglucuronic acid. UGTs are anchored in endoplasmic reticulum, ER, by transmembrane fragment of C-terminal domain. The membrane location results in the latency of enzyme activity and demands specific transporters for cofactor as well as for conjugation products. There are NST and AT(ER), respectively. UDP-glucuronyltransferases exist usually as homo- and heterodimers, some of them are tetramers. 19 human UGT proteins are described by 3 gene subfamilies, UGT1A, UGT2A and UGT2B, which are expressed preferentially in the liver, but also in stomach, lung and intestine epithelium.
authors: Katedra Technologii Leków i Biochemii, Wydział Chemiczny, Politechnika Gdańska, ul Narutowicza 11/12, 80-233 Gdańsk.
authors: Barbara
authors: B
authors: Fedejko
authors: Zofia
authors: Z
authors: Mazerska
mesh_terms: D004721:Endoplasmic Reticulum / Q000201:enzymology*; D005753:Gastric Mucosa / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism
chemical_list: D014453:Glucuronosyltransferase