Enzymes
UniProtKB help_outline | 211 proteins |
Reaction participants Show >> << Hide
- Name help_outline (5Z,8Z,11Z,14Z)-eicosatetraenoate Identifier CHEBI:32395 (Beilstein: 5439048) help_outline Charge -1 Formula C20H31O2 InChIKeyhelp_outline YZXBAPSDXZZRGB-DOFZRALJSA-M SMILEShelp_outline CCCCC\C=C/C\C=C/C\C=C/C\C=C/CCCC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 83 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 2,727 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline (15R)-hydroperoxy-(5Z,8Z,11Z,13E)-eicosatetraenoate Identifier CHEBI:82626 Charge -1 Formula C20H31O4 InChIKeyhelp_outline BFWYTORDSFIVKP-UDQWCNDOSA-M SMILEShelp_outline CCCCC[C@@H](OO)\C=C\C=C/C\C=C/C\C=C/CCCC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:42284 | RHEA:42285 | RHEA:42286 | RHEA:42287 | |
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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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Analysis of hydroperoxide-induced tyrosyl radicals and lipoxygenase activity in aspirin-treated human prostaglandin H synthase-2.
Xiao G., Tsai A.L., Palmer G., Boyar W.C., Marshall P.J., Kulmacz R.J.
A hydroperoxide-induced tyrosyl radical has been proposed as a key cyclooxygenase intermediate for the "basal" isoform of prostaglandin H synthase (PGHS-1). In the present study with the "inducible" isoform (PGHS-2), hydroperoxide was also found to generate a radical in high yield, a wide singlet ... >> More
A hydroperoxide-induced tyrosyl radical has been proposed as a key cyclooxygenase intermediate for the "basal" isoform of prostaglandin H synthase (PGHS-1). In the present study with the "inducible" isoform (PGHS-2), hydroperoxide was also found to generate a radical in high yield, a wide singlet at g = 2.0058 (29 G peak to trough). Reaction of PGHS-2 with a tyrosine-modifying reagent, tetranitromethane (TNM), resulted in cyclooxygenase inactivation and a much narrower radical EPR signal (22 G peak to trough). Addition of a cyclooxygenase inhibitor, nimesulide, similarly resulted in a narrow PGHS-2 radical. In PGHS-1, cyclooxygenase inhibition by tyrosine nitration with TNM or by active site ligands leads to generation of a narrow EPR instead of a wide EPR, with both signals originating from authentic tyrosyl radicals, indicating that the hydroperoxide-induced radicals in PGHS-2 are also tyrosyl radicals. Treatment of PGHS-2 with aspirin (acetyl salicylic acid, ASA) was previously shown to result in acetylation of a specific serine residue, cyclooxygenase inhibition, and increased lipoxygenase activity. Acetylation of PGHS-1 by ASA, in contrast, inhibited both lipoxygenase and cyclooxygenase activity. We now have found the ASA-treated PGHS-2 radical to be indistinguishable from that in control PGHS-2. Addition of nimesulide to ASA-treated PGHS-2 inhibited the lipoxygenase and resulted in a narrow radical EPR like that seen in PGHS-2 treated with TNM or nimesulide alone. Retention of PGHS-2 oxygenase activity was thus associated with retention of the native radical, and loss of activity was associated with alteration of the radical. Both native and ASA-treated PGHS-2 produced only the R stereoisomer of 11- and 15-HETE, demonstrating that the lipoxygenase stereochemistry was not changed by ASA. Native and ASA-treated PGHS-2 had lipoxygenase K(m) values considerably higher than that of the control PGHS-2 cyclooxygenase. Taken together, these results suggest that the same PGHS-2 tyrosyl radical serves as the oxidant for both cyclooxygenase and lipoxygenase catalysis and that acetylation of PGHS-2 by ASA favors arachidonate binding in an altered conformation which results in abstraction of the pro-R hydrogen from C13 and formation of 11(R)- and 15(R)-HETE. << Less
Biochemistry 36:1836-1845(1997) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.