Enzymes
| UniProtKB help_outline | 5 proteins |
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- Name help_outline epitestosterone Identifier CHEBI:42534 (CAS: 481-30-1) help_outline Charge 0 Formula C19H28O2 InChIKeyhelp_outline MUMGGOZAMZWBJJ-KZYORJDKSA-N SMILEShelp_outline C[C@]12CC[C@H]3[C@@H](CCC4=CC(=O)CC[C@]34C)[C@@H]1CC[C@H]2O 2D coordinates Mol file for the small molecule Search links Involved in 2 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 94 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline epitestosterone 17-O-(β-D-glucuronate) Identifier CHEBI:136673 Charge -1 Formula C25H35O8 InChIKeyhelp_outline NIKZPECGCSUSBV-RWUBDERLSA-M SMILEShelp_outline [C@@]12([C@@]([C@@]3(C(CC1)=CC(CC3)=O)C)(CC[C@]4(C)[C@@H](CC[C@@]24[H])O[C@@H]5O[C@@H]([C@H]([C@@H]([C@H]5O)O)O)C([O-])=O)[H])[H] 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 9,176 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 542 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:52568 | RHEA:52569 | RHEA:52570 | RHEA:52571 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Publications
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UDP-glucuronosyltransferases (UGTs) 2B7 and UGT2B17 display converse specificity in testosterone and epitestosterone glucuronidation, whereas UGT2A1 conjugates both androgens similarly.
Sten T., Bichlmaier I., Kuuranne T., Leinonen A., Yli-Kauhaluoma J., Finel M.
Testosterone and epitestosterone are endogenous steroids that differ in the configuration of the hydroxyl-bearing carbon at C-17. Testosterone is the predominant male sex hormone, whereas the role of epitestosterone is largely unclear. In humans, both androgens are excreted mainly as glucuronide c ... >> More
Testosterone and epitestosterone are endogenous steroids that differ in the configuration of the hydroxyl-bearing carbon at C-17. Testosterone is the predominant male sex hormone, whereas the role of epitestosterone is largely unclear. In humans, both androgens are excreted mainly as glucuronide conjugates and the urinary ratio of testosterone to epitestosterone (T/E), used to expose illicit testosterone abuse by male athletes, indicates the relative concentrations of the respective glucuronides. Some male athletes have T/E values greater than the accepted threshold value (4.0), even without testosterone abuse. We have analyzed athletes' urine samples and found that the main reason for such false-positive results in doping tests was a low epitestosterone glucuronide concentration not a high level of testosterone glucuronide. Sulfate conjugates of both testosterone and epitestosterone were also detected in the different urine samples. Glucuronidation assays with the 19 human UDP-glucuronosyltransferases (UGTs) of subfamilies UGT1A, UGT2A, and UGT2B revealed that UGT2B17 is the most active enzyme in testosterone glucuronidation. UGT2B17 does not glucuronidate epitestosterone, but inhibition studies revealed that it binds epitestosterone with affinity similar to that of testosterone. Epitestosterone glucuronidation is catalyzed mainly by UGT2B7, and the K(m) of this reaction is significantly lower than the K(m) of UGT2B17 for testosterone. Although UGT2B7 and UGT2B17 exhibited high, although converse, stereoselectivity in testosterone and epitestosterone glucuronidation, UGT2A1, an extrahepatic enzyme that is expressed mainly in the nasal epithelium, catalyzed the glucuronidation of both steroids at considerable rates and similar kinetics. The results shed new light on the substrate specificity and stereoselectivity of human UGTs. << Less
Drug Metab. Dispos. 37:417-423(2009) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.