Enzymes
| UniProtKB help_outline | 2 proteins |
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- Name help_outline calcitriol Identifier CHEBI:17823 (Beilstein: 2227647; CAS: 32222-06-3) help_outline Charge 0 Formula C27H44O3 InChIKeyhelp_outline GMRQFYUYWCNGIN-NKMMMXOESA-N SMILEShelp_outline [H][C@@]1(CC[C@@]2([H])\C(CCC[C@]12C)=C\C=C1\C[C@@H](O)C[C@H](O)C1=C)[C@H](C)CCCC(C)(C)O 2D coordinates Mol file for the small molecule Search links Involved in 7 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP-α-D-glucuronate Identifier CHEBI:58052 Charge -3 Formula C15H19N2O18P2 InChIKeyhelp_outline HDYANYHVCAPMJV-LXQIFKJMSA-K SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])(=O)O[C@H]2O[C@@H]([C@@H](O)[C@H](O)[C@H]2O)C([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 107 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline calcitriol 25-O-(β-D-glucuronide) Identifier CHEBI:139274 Charge -1 Formula C33H51O9 InChIKeyhelp_outline UBEXJJQDSPZXNL-BHNPUNFPSA-M SMILEShelp_outline C1[C@]2([C@](/C(=C/C=C/3\C([C@H](C[C@@H](C3)O)O)=C)/CC1)(CC[C@@]2([C@H](C)CCCC(O[C@@H]4O[C@@H]([C@H]([C@@H]([C@H]4O)O)O)C(=O)[O-])(C)C)[H])[H])C 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP Identifier CHEBI:58223 Charge -3 Formula C9H11N2O12P2 InChIKeyhelp_outline XCCTYIAWTASOJW-XVFCMESISA-K SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 576 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:55836 | RHEA:55837 | RHEA:55838 | RHEA:55839 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Related reactions help_outline
More general form(s) of this reaction
Publications
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Identification of human UDP-glucuronosyltransferases catalyzing hepatic 1alpha,25-dihydroxyvitamin D3 conjugation.
Hashizume T., Xu Y., Mohutsky M.A., Alberts J., Hadden C., Kalhorn T.F., Isoherranen N., Shuhart M.C., Thummel K.E.
The biological effects of 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) are terminated primarily by P450-dependent hydroxylation reactions. However, the hormone is also conjugated in the liver and a metabolite, presumably a glucuronide, undergoes enterohepatic cycling. In this study, the identity of ... >> More
The biological effects of 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) are terminated primarily by P450-dependent hydroxylation reactions. However, the hormone is also conjugated in the liver and a metabolite, presumably a glucuronide, undergoes enterohepatic cycling. In this study, the identity of human enzymes capable of catalyzing the 1,25(OH)2D3 glucuronidation reaction was investigated in order to better understand environmental and endogenous factors affecting the disposition and biological effects of vitamin D3. Among 12 different UGT isozymes tested, only UGT1A4 >> 2B4 and 2B7 supported the reaction. Two different 1,25(OH)2D3 monoglucuronide metabolites were generated by recombinant UGT1A4 and human liver microsomes. The most abundant product was identified by mass spectral and NMR analyses as the 25-O-glucuronide isomer. The formation of 25-O-glucuronide by UGT1A4 Supersomes and human liver microsomes followed simple hyperbolic kinetics, yielding respective Km and Vmax values of 7.3 and 11.2 microM and 33.7 +/- 1.4 and 32.9 +/-1.9 pmol/min/mg protein. The calculated intrinsic 25-O-glucuronide M1 formation clearance for UGT1A4 was 14-fold higher than the next best isozyme, UGT2B7. There was only limited (four-fold) inter-liver variability in the 25-O-glucuronidation rate, but it was highly correlated with the relative rate of formation of the second, minor metabolite. In addition, formation of both metabolites was inhibited >80% by the selective UGT1A4 inhibitor, hecogenin. If enterohepatic recycling of 1,25(OH)2D3 represents a significant component of intestinal and systemic 1,25(OH)2D3 disposition, formation of monoglucuronides by hepatic UGT1A4 constitutes an important initial step. << Less