Enzymes
| UniProtKB help_outline | 2 proteins |
Reaction participants Show >> << Hide
- Name help_outline cholesterol Identifier CHEBI:16113 (Beilstein: 2060565; CAS: 57-88-5) help_outline Charge 0 Formula C27H46O InChIKeyhelp_outline HVYWMOMLDIMFJA-DPAQBDIFSA-N SMILEShelp_outline C1[C@@]2([C@]3(CC[C@]4([C@]([C@@]3(CC=C2C[C@H](C1)O)[H])(CC[C@@]4([C@H](C)CCCC(C)C)[H])[H])C)[H])C 2D coordinates Mol file for the small molecule Search links Involved in 63 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 (22R)-hydroxycholesterol Identifier CHEBI:67237 (CAS: 17954-98-2) help_outline Charge 0 Formula C27H46O2 InChIKeyhelp_outline RZPAXNJLEKLXNO-GFKLAVDKSA-N SMILEShelp_outline [H][C@@]1(CC[C@@]2([H])[C@]3([H])CC=C4C[C@@H](O)CC[C@]4(C)[C@@]3([H])CC[C@]12C)[C@H](C)[C@H](O)CCC(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:46140 | RHEA:46141 | RHEA:46142 | RHEA:46143 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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| MetaCyc help_outline |
Publications
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A cytochrome P450 monooxygenase responsible for the C-22 hydroxylation step in the Paris polyphylla steroidal saponin biosynthesis pathway.
Yin Y., Gao L., Zhang X., Gao W.
Polyphyllins are the major steroidal saponin components of Paris polyphylla, the main source plant of the common Chinese herbal medicine Paridis Rhizoma with strong pharmacological activity and extremely high economic value and great market prospects. However, the production of polyphyllins in pla ... >> More
Polyphyllins are the major steroidal saponin components of Paris polyphylla, the main source plant of the common Chinese herbal medicine Paridis Rhizoma with strong pharmacological activity and extremely high economic value and great market prospects. However, the production of polyphyllins in plants is limited, and their biosynthesis pathway has not been reported. The downstream hydroxylation step was particularly unclear. To clarify the enzymes and intermediates involved in the downstream steps of polyphyllin biosynthesis, we performed a comparative transcriptome analysis and discovered a cytochrome P450 gene that encodes a protein with monooxygenase activity. Heterologous expression in Saccharomyces cerevisiae demonstrated that it encodes an enzyme that catalyzes the formation of 22(R)-hydroxycholesterol from cholesterol. The relative gene expression measured by RT-PCR and polyphyllin contents measured by HPLC in P. polyphylla roots at different ages confirmed that this gene is involved in polyphyllin biosynthesis. To our best knowledge, this is the first report on the cloning of a CYP450 enzyme gene from the steroidal saponin pathway of higher plants. << Less
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Cholesterol 25-hydroxylation activity of CYP3A.
Honda A., Miyazaki T., Ikegami T., Iwamoto J., Maeda T., Hirayama T., Saito Y., Teramoto T., Matsuzaki Y.
To date, many studies have been conducted using 25-hydroxycholesterol, which is a potent regulator of lipid metabolism. However, the origins of this oxysterol have not been entirely elucidated. Cholesterol 25-hydroxylase is one of the enzymes responsible for the metabolism of 25-hydroxycholesterol ... >> More
To date, many studies have been conducted using 25-hydroxycholesterol, which is a potent regulator of lipid metabolism. However, the origins of this oxysterol have not been entirely elucidated. Cholesterol 25-hydroxylase is one of the enzymes responsible for the metabolism of 25-hydroxycholesterol, but the expression of this enzyme is very low in humans. This oxysterol is also synthesized by sterol 27-hydroxylase (CYP27A1) and cholesterol 24-hydroxylase(CYP46A1), but it is only a minor product of these enzymes. We now report that CYP3A synthesizes a significant amount of 25-hydroxycholesterol and may participate in the regulation of lipid metabolism. Induction of CYP3A by pregnenolone-16α-carbonitrile caused the accumulation of 25-hydroxycholesterol in a cell line derived from mouse liver. Furthermore, treatment of the cells with troleandomycin, a specific inhibitor of CYP3A, significantly reduced cellular 25-hydroxycholesterol concentrations. In cells that overexpressed human recombinant CYP3A4, the activity of cholesterol 25-hydroxylation was found to be higher than that of cholesterol 4β-hydroxylation, a known marker activity of CYP3A4. In addition, 25-hydroxycholesterol concentrations in normal human sera correlated positively with the levels of 4β-hydroxycholesterol (r = 0.650, P < 0.0001, n = 78), but did not significantly correlate with the levels of 27-hydroxycholesterol or 24S-hydroxycholesterol. These results demonstrate the significance of CYP3A on the production of 25-hydroxycholesterol. << Less
J. Lipid Res. 52:1509-1516(2011) [PubMed] [EuropePMC]
This publication is cited by 4 other entries.