Component
The cyclooxygenase active-site tyrosyl radical
The cyclooxygenase active-site tyrosyl radical. Species, exposure and limitations are retained in each linked claim.
1 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
How nutrients influence it
Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
How nutrients reach it in more than one step
Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.
Tracing routes…
What it does
Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.
Where it participates (unsigned role)
Reduction of prostaglandin H synthase compound II to native enzyme by phenol proceeded with a second-order rate constant of 5.3 x 10(5) per molar per second and by hydroquinone at 2.1 x 10(6), rapid scan spectra also showed reduction of compound I to compound II by both so that reduction of both compounds is a one-electron process, and the results suggest the tyrosyl radical detected in the presence of oxidizing agents is formed by intramolecular electron transfer from the tyrosyl residue to the porphyrin pi-cation radical and tends to disappear in the presence of sufficient reducing substrate.
Experimental context and source evidence
- evidence_span
- {"source_cache": "artifacts/paracetamol-research/1727638.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "028284c7b657c213a3052d362a0a5d050b1678d9ab3c5403b8e68d3631494c0c", "start_char": 0, "end_char": 1789, "text_sha256": "028284c7b657c213a3052d362a0a5d050b1678d9ab3c5403b8e68d3631494c0c"}
- experimental_model
- Rapid scan spectrometry and transient state kinetics of prostaglandin H synthase compound II reduction
- exposure
- Phenol and hydroquinone as reducing cosubstrates, with indomethacin
- limitations
- Measures the reduction step directly with rate constants rather than inferring it from inhibition. It uses phenol and hydroquinone rather than paracetamol, which is recorded on the claim.
- nutrient_topic
- Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol
- organism
- Enzyme
- plain_language
- A phenol hands the enzyme one electron at a time, and enough of it makes the radical the enzyme needs disappear.
- primary_references
- [apap-p1727638] Reduction of prostaglandin H synthase compound II by phenol and hydroquinone, and the effect of indomethacin. (1992). https://pubmed.ncbi.nlm.nih.gov/1727638/ DOI: 10.1016/0003-9861(92)90070-d
- tissue_or_cell_type
- Purified prostaglandin H synthase
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Rapid scan spectrometry and transient state kinetics of prostaglandin H synthase compound II reduction · source_derived_draft · unverified_draft
### apap-one-electron-reduction Reduction of prostaglandin H synthase compound II to native enzyme by phenol proceeded with a second-order rate constant of 5.3 x 10(5) per molar per second and by hydroquinone at 2.1 x 10(6), rapid scan spectra also showed reduction of compound I to compound II by both so that reduction of both compounds is a one-electron process, and the results suggest the tyrosyl radical detected in the presence of oxidizing agents is formed by intramolecular electron transfer from the tyrosyl residue to the porphyrin pi-cation radical and tends to disappear in the presence of sufficient reducing substrate. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: A phenol hands the enzyme one electron at a time, and enough of it makes the radical the enzyme needs disappear. organism: Enzyme tissue_or_cell_type: Purified prostaglandin H synthase experimental_model: Rapid scan spectrometry and transient state kinetics of prostaglandin H synthase compound II reduction limitations: Measures the reduction step directly with rate constants rather than inferring it from inhibition. It uses phenol and hydroquinone rather than paracetamol, which is recorded on the claim. exposure: Phenol and hydroquinone as reducing cosubstrates, with indomethacin evidence_span: {"source_cache": "artifacts/paracetamol-research/1727638.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "028284c7b657c213a3052d362a0a5d050b1678d9ab3c5403b8e68d3631494c0c", "start_char": 0, "end_char": 1789, "text_sha256": "028284c7b657c213a3052d362a0a5d050b1678d9ab3c5403b8e68d3631494c0c"} [apap-p1727638] Reduction of prostaglandin H synthase compound II by phenol and hydroquinone, and the effect of indomethacin. (1992). https://pubmed.ncbi.nlm.nih.gov/1727638/ DOI: 10.1016/0003-9861(92)90070-d
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.