Reaction participants Show >> << Hide
- Name help_outline bilirubin-glucuronoside Identifier CHEBI:57767 Charge -2 Formula C39H42N4O12 InChIKeyhelp_outline ARBDURHEPGRPSR-GEADQAOESA-L SMILEShelp_outline CC1=C(C=C)\C(NC1=O)=C/c1[nH]c(Cc2[nH]c(\C=C3NC(=O)C(C=C)=C\3C)c(C)c2CCC([O-])=O)c(CCC(=O)O[C@@H]2O[C@@H]([C@@H](O)[C@H](O)[C@H]2O)C([O-])=O)c1C 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline bilirubin IXα Identifier CHEBI:57977 (Beilstein: 4083310) help_outline Charge -2 Formula C33H34N4O6 InChIKeyhelp_outline BPYKTIZUTYGOLE-IFADSCNNSA-L SMILEShelp_outline CC1=C(C=C)\C(NC1=O)=C\c1[nH]c(Cc2[nH]c(\C=C3NC(=O)C(C=C)=C/3C)c(C)c2CCC([O-])=O)c(CCC([O-])=O)c1C 2D coordinates Mol file for the small molecule Search links Involved in 5 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline bilirubin-bisglucuronoside Identifier CHEBI:58471 Charge -2 Formula C45H50N4O18 InChIKeyhelp_outline SCJLWMXOOYZBTH-SDXZDYKGSA-L SMILEShelp_outline CC1=C(C=C)\C(NC1=O)=C/c1[nH]c(Cc2[nH]c(\C=C3NC(=O)C(C=C)=C\3C)c(C)c2CCC(=O)O[C@@H]2O[C@@H]([C@@H](O)[C@H](O)[C@H]2O)C([O-])=O)c(CCC(=O)O[C@@H]2O[C@@H]([C@@H](O)[C@H](O)[C@H]2O)C([O-])=O)c1C 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:16885 | RHEA:16886 | RHEA:16887 | RHEA:16888 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Uridine diphosphate-glucuronic acid-independent conversion of bilirubin monoglucuronides to diglucuronide in presence of plasma membranes from rat liver is nonenzymic.
Sieg A., van Hees G.P., Heirwegh K.P.
TWO ROUTES HAVE BEEN PROPOSED FOR CONVERSION OF BILIRUBIN MONOGLUCURONIDE TO THE DIGLUCURONIDE: glucuronyl transfer (a) from UDP-glucuronic acid to bilirubin monoglucuronide, catalyzed by a microsomal UDP-glucuronyltransferase, and (b) from one molecule of bilirubin monoglucuronide to another (tra ... >> More
TWO ROUTES HAVE BEEN PROPOSED FOR CONVERSION OF BILIRUBIN MONOGLUCURONIDE TO THE DIGLUCURONIDE: glucuronyl transfer (a) from UDP-glucuronic acid to bilirubin monoglucuronide, catalyzed by a microsomal UDP-glucuronyltransferase, and (b) from one molecule of bilirubin monoglucuronide to another (transglucuronidation), catalyzed by an enzyme present in liver plasma membranes. The evidence regarding the role of the latter enzyme for in vivo formation of bilirubin diglucuronide is conflicting. We therefore decided to reexamine the transglucuronidation reaction in plasma membranes and to study the conversion of bilirubin monoglucuronide to diglucuronide in vivo. Purified bilirubin monoglucuronide was incubated with homogenates and plasma membrane-enriched fractions from liver of Wistar and Gunn rats. Stoichiometric formation of bilirubin and bilirubin diglucuronide out of 2 mol of bilirubin monoglucuronide was paralleled by an increase of the IIIalpha- and XIIIalpha-isomers of the bilirubin aglycone, thus showing that dipyrrole exchange, not transglucuronidation, is the underlying mechanism. Complete inhibition by ascorbic acid probably reflects intermediate formation of free radicals of dipyrrolic moieties. The reaction was nonenzymic because it proceeded independently of the protein concentration and heat denaturation of the plasma membranes did not result in decreased conversion rates. Collectively, these findings show spontaneous, nonenzymic dipyrrole exchange when bilirubin monoglucuronide is incubated in the presence of rat liver plasma membranes. Because bilirubin glucuronides present in biological fluids contain exclusively the bilirubin-IXalpha aglycone, formation of the diglucuronide from the monoglucuronide by dipyrrole exchange does not occur in vivo. Rapid excretion of unchanged bilirubin monoglucuronide in Gunn rat bile after injection of the pigment provides confirmatory evidence for the absence of a UDP-glucuronic acid-independent process. << Less
Comments
According to PMID:7056852, this reaction occurs spontaneously.