Enzymes
| UniProtKB help_outline | 10 proteins |
| Enzyme class help_outline |
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- Name help_outline 4-nitrophenol Identifier CHEBI:57917 (Beilstein: 3589511) help_outline Charge -1 Formula C6H4NO3 InChIKeyhelp_outline BTJIUGUIPKRLHP-UHFFFAOYSA-M SMILEShelp_outline [O-]c1ccc(cc1)[N+]([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 6 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 NADPH Identifier CHEBI:57783 (Beilstein: 10411862) help_outline Charge -4 Formula C21H26N7O17P3 InChIKeyhelp_outline ACFIXJIJDZMPPO-NNYOXOHSSA-J SMILEShelp_outline NC(=O)C1=CN(C=CC1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](OP([O-])([O-])=O)[C@@H]2O)n2cnc3c(N)ncnc23)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1,247 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
- Name help_outline 4-nitrocatechol Identifier CHEBI:57730 Charge -1 Formula C6H4NO4 InChIKeyhelp_outline XJNPNXSISMKQEX-UHFFFAOYSA-M SMILEShelp_outline C1(=CC=C(C=C1O)[N+]([O-])=O)[O-] 2D coordinates Mol file for the small molecule Search links Involved in 6 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
- Name help_outline NADP+ Identifier CHEBI:58349 Charge -3 Formula C21H25N7O17P3 InChIKeyhelp_outline XJLXINKUBYWONI-NNYOXOHSSA-K SMILEShelp_outline NC(=O)c1ccc[n+](c1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](OP([O-])([O-])=O)[C@@H]2O)n2cnc3c(N)ncnc23)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1,253 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:26205 | RHEA:26206 | RHEA:26207 | RHEA:26208 | |
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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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Both cytochromes P450 2E1 and 3A are involved in the O-hydroxylation of p-nitrophenol, a catalytic activity known to be specific for P450 2E1.
Zerilli A., Ratanasavanh D., Lucas D., Goasduff T., Dreano Y., Menard C., Picart D., Berthou F.
4-Nitrophenol 2-hydroxylation activity was previously shown to be mainly catalyzed by P450 2E1 in animal species and humans. As this chemical compound is widely used as an in vitro probe for P450 2E1, this study was carried out to test its catalytic specificity. First, experiments were carried out ... >> More
4-Nitrophenol 2-hydroxylation activity was previously shown to be mainly catalyzed by P450 2E1 in animal species and humans. As this chemical compound is widely used as an in vitro probe for P450 2E1, this study was carried out to test its catalytic specificity. First, experiments were carried out on liver microsomes and hepatocyte cultures of rat treated with different inducers. Liver microsomes from pyrazole- and dexamethasone-treated rats hydroxylated p-nitrophenol with a metabolic rate increased by 2.5- and 2.7-fold vs control. Dexamethasone treatment increased the hepatic content of P450 3A but not that of P450 2E1. Two specific inhibitors of P450 3A catalytic activities, namely, ketoconazole and troleandomycin (TAO), inhibited up to 50% of 4-nitrophenol hydroxylation in dexamethasone-treated rats but not in controls. Hepatocyte cultures from dexamethasone-treated rats transformed p-nitrophenol into 4-nitrocatechol 7.8 times more than controls. This catalytic activity was inhibited by TAO. Similarly, hepatocyte cultures from pyrazole-treated rats hydroxylated p-nitrophenol with a metabolic ratio increased by about 8-fold vs control. This reaction was inhibited by diethyl dithiocarbamate and dimethyl sulfoxide, both inhibitors of P450 2E1. Second, the capability of human P450s other than P450 2E1 to catalyze the formation of 4-nitrocatechol was examined in a panel of 13 human liver microsomes. Diethyl dithiocarbamate and ketoconazole reduced 4-nitrophenol hydroxylase activity by 77% (+/-11) and 13% (+/-16), respectively. Furthermore, the residual activity following diethyl dithiocarbamate inhibition was significantly correlated with seven P450 3A4 catalytic activities. Finally, the use of human cell lines genetically engineered for expression of human P450s demonstrated that P450 2E1 and 3A4 hydroxylated 4-nitrophenol with turnovers of 19.5 and 1.65 min-1, respectively. In conclusion, P450 3A may make a significant contribution to 4-nitrophenol hydroxylase activity in man and rat. << Less