Reaction: UGT1A1 tetramer transfers GlcA from UDP-GlcA to BMG to form BDG
- in pathway: Heme degradation
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).
Reaction - small molecule participants:
BDG [endoplasmic reticulum lumen]
UDP [endoplasmic reticulum lumen]
BMG [endoplasmic reticulum lumen]
UDP-GlcA [endoplasmic reticulum lumen]
BDG [endoplasmic reticulum lumen]
UDP [endoplasmic reticulum lumen]
BMG [endoplasmic reticulum lumen]
UDP-GlcA [endoplasmic reticulum lumen]
Reactome.org reaction link: R-HSA-9632038
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Reaction input - small molecules:
mono(glucosyluronic acid)bilirubin
UDP-alpha-D-glucuronate(3-)
mono(glucosyluronic acid)bilirubin
UDP-alpha-D-glucuronate(3-)
Reaction output - small molecules:
bis(beta-glucosyluronate)bilirubin
UDP
bis(beta-glucosyluronate)bilirubin
UDP
Reactome.org link: R-HSA-9632038