UGT1A1 tetramer transfers GlcA from UDP-GlcA to BMG to form BDG

Stable Identifier
Reaction [transition]
Homo sapiens
bilirubin monoglucuronide + UDP-glucuronic acid => bilirubin diglucuronide + UDP
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The principal conjugate of bilirubin in bile is bilirubin diglucuronide (BDG). The monomeric forms of UGT1A1 (Bilirubin UDP-glucuronyltransferase 1) only conjugates the first step of bilirubin conjugation to form the monoglucuronide. A tetrameric form of UGT1A1 can transfer glucuronic acid (GlcA) to bilirubin (BIL) and bilirubin monoglucuronide (BMG) to form both the monoglucuronide and the diglucuronide (BDG) conjugates respectively (Peters & Jansen 1986, Gorden et al. 1983, Choudhury et al. 1981, Fevery et al. 1971).

Literature References
PubMed ID Title Journal Year
4639028 Bilirubin conjugates in bile of man and rat in the normal state and in liver disease

Michiels, R, Van, Damme B, Heirwegh, KP, Fevery, J, De Groote, J

J Clin Invest 1972
6654901 The hepatic microsomal formation of bilirubin diglucuronide

Goresky, CA, Gordon, ER, Sommerer, U

J Biol Chem 1983
6796486 Bilirubin mono- and diglucuronide formation by human liver in vitro: assay by high-pressure liquid chromatography

Shouval, R, Wu, G, Chowdhury, JR, Chowdhury, NR, Arias, IM

Hepatology 1981
3082969 Microsomal UDP-glucuronyltransferase-catalyzed bilirubin diglucuronide formation in human liver

Jansen, PL, Peters, WH

J Hepatol 1986
Catalyst Activity

glucuronosyltransferase activity of UGT1A1 tetramer [endoplasmic reticulum membrane]

Orthologous Events
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