Enzymes
| UniProtKB help_outline | 5 proteins |
Reaction participants Show >> << Hide
- Name help_outline 7-dehydrocholesterol Identifier CHEBI:17759 (Beilstein: 2224615; CAS: 434-16-2) help_outline Charge 0 Formula C27H44O InChIKeyhelp_outline UCTLRSWJYQTBFZ-DDPQNLDTSA-N SMILEShelp_outline [H][C@@]1(CC[C@@]2([H])C3=CC=C4C[C@@H](O)CC[C@]4(C)[C@@]3([H])CC[C@]12C)[C@H](C)CCCC(C)C 2D coordinates Mol file for the small molecule Search links Involved in 12 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline O2 Identifier CHEBI:15379 (CAS: 7782-44-7) help_outline Charge 0 Formula O2 InChIKeyhelp_outline MYMOFIZGZYHOMD-UHFFFAOYSA-N SMILEShelp_outline O=O 2D coordinates Mol file for the small molecule Search links Involved in 2,648 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
reduced [NADPH—hemoprotein reductase]
Identifier
RHEA-COMP:11964
Reactive part
help_outline
- Name help_outline FMNH2 Identifier CHEBI:57618 (Beilstein: 6258176) help_outline Charge -2 Formula C17H21N4O9P InChIKeyhelp_outline YTNIXZGTHTVJBW-SCRDCRAPSA-L SMILEShelp_outline Cc1cc2Nc3c([nH]c(=O)[nH]c3=O)N(C[C@H](O)[C@H](O)[C@H](O)COP([O-])([O-])=O)c2cc1C 2D coordinates Mol file for the small molecule Search links Involved in 771 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 7-oxocholesterol Identifier CHEBI:64294 (Beilstein: 2169084; CAS: 566-28-9) help_outline Charge 0 Formula C27H44O2 InChIKeyhelp_outline YIKKMWSQVKJCOP-ABXCMAEBSA-N SMILEShelp_outline [H][C@@]1(CC[C@@]2([H])[C@]3([H])C(=O)C=C4C[C@@H](O)CC[C@]4(C)[C@@]3([H])CC[C@]12C)[C@H](C)CCCC(C)C 2D coordinates Mol file for the small molecule Search links Involved in 4 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 H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,048 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
oxidized [NADPH—hemoprotein reductase]
Identifier
RHEA-COMP:11965
Reactive part
help_outline
- Name help_outline FMN Identifier CHEBI:58210 Charge -3 Formula C17H18N4O9P InChIKeyhelp_outline ANKZYBDXHMZBDK-SCRDCRAPSA-K SMILEShelp_outline C12=NC([N-]C(C1=NC=3C(N2C[C@@H]([C@@H]([C@@H](COP(=O)([O-])[O-])O)O)O)=CC(=C(C3)C)C)=O)=O 2D coordinates Mol file for the small molecule Search links Involved in 781 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:53248 | RHEA:53249 | RHEA:53250 | RHEA:53251 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Publications
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Conversion of 7-dehydrocholesterol to 7-ketocholesterol is catalyzed by human cytochrome P450 7A1 and occurs by direct oxidation without an epoxide intermediate.
Shinkyo R., Xu L., Tallman K.A., Cheng Q., Porter N.A., Guengerich F.P.
7-Ketocholesterol is a bioactive sterol, a potent competitive inhibitor of cytochrome P450 7A1, and toxic in liver cells. Multiple origins of this compound have been identified, with cholesterol being the presumed precursor. Although routes for formation of the 7-keto compound from cholesterol hav ... >> More
7-Ketocholesterol is a bioactive sterol, a potent competitive inhibitor of cytochrome P450 7A1, and toxic in liver cells. Multiple origins of this compound have been identified, with cholesterol being the presumed precursor. Although routes for formation of the 7-keto compound from cholesterol have been established, we found that 7-dehydrocholesterol (the immediate precursor of cholesterol) is oxidized by P450 7A1 to 7-ketocholesterol (k(cat)/K(m) = 3 × 10(4) m(-1) s(-1)). P450 7A1 converted lathosterol (Δ(5)-dihydro-7-dehydrocholesterol) to a mixture of the 7-keto and 7α,8α-epoxide products (~1:2 ratio), with the epoxide not rearranging to the ketone. The oxidation of 7-dehydrocholesterol occured with predominant formation of 7-ketocholesterol and with the 7α,8α-epoxide as only a minor product; the synthesized epoxide was stable in the presence of P450 7A1. The mechanism of 7-dehydrocholesterol oxidation to 7-ketocholesterol is proposed to involve a Fe(III)-O-C-C(+) intermediate and a 7,8-hydride shift or an alternative closing to yield the epoxide (Liebler, D. C., and Guengerich, F. P. (1983) Biochemistry 22, 5482-5489). Accordingly, reaction of P450 7A1 with 7-[(2)H(1)]dehydrocholesterol yielded complete migration of deuterium in the product 7-ketocholesterol. The finding that 7-dehydrocholesterol is a precursor of 7-ketocholesterol has relevance to an inborn error of metabolism known as Smith-Lemli-Opitz syndrome (SLOS) caused by defective cholesterol biosynthesis. Mutations within the gene encoding 7-dehydrocholesterol reductase, the last enzyme in the pathway, lead to the accumulation of 7-dehydrocholesterol in tissues and fluids of SLOS patients. Our findings suggest that 7-ketocholesterol levels may also be elevated in SLOS tissue and fluids as a result of P450 7A1 oxidation of 7-dehydrocholesterol. << Less
J. Biol. Chem. 286:33021-33028(2011) [PubMed] [EuropePMC]
This publication is cited by 2 other entries.