Component
The volume of the cyclooxygenase-2 active site relative to that of cyclooxygenase-1
The volume of the cyclooxygenase-2 active site relative to that of cyclooxygenase-1. 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)
When microsomal human cyclooxygenase-2 was incubated with acetyl-carbon-14 labelled aspirin the enzyme was acetylated, while an S516A mutant which retains enzyme activity was not acetylated, indicating that Ser-516 is the site of aspirin acetylation and is homologous to the active site serine of cyclooxygenase-1; an S516N mutant was catalytically active whereas an S516Q mutant lacked cyclooxygenase but retained peroxidase activity, and because in cyclooxygenase-1 the smaller asparagine substitution suffices to eliminate cyclooxygenase activity the active site of cyclooxygenase-2 is slightly larger.
Experimental context and source evidence
- evidence_span
- {"source_cache": "artifacts/aspirin-research/8175750.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9ba85af90c62b157cf53032375ca703e8b78eff6ddd22ad627bbd7e65965d8e9", "start_char": 0, "end_char": 1786, "text_sha256": "9ba85af90c62b157cf53032375ca703e8b78eff6ddd22ad627bbd7e65965d8e9"}
- experimental_model
- Human cyclooxygenase-1 and -2 expressed in cos-1 cells treated with aspirin and with carbon-14 labelled aspirin, with a mutant series at Ser-516
- exposure
- Aspirin acetylation, with S516A, S516N, S516Q and S516M substitutions
- limitations
- Identifies the site by direct labelling and explains the isoform difference by active site volume. Recombinant enzyme in a heterologous cell line.
- nutrient_topic
- Aspirin research collection; topical membership is not evidence of a direct clinical effect, and aspirin is recorded separately from salicylate, the metabolite it becomes. · Aspirin / acetylsalicylic acid
- organism
- Human enzyme
- plain_language
- The labelled acetyl group lands on one serine, and the second enzyme’s pocket is roomier, which is why the two behave differently.
- primary_references
- [asa-p8175750] Acetylation of human prostaglandin endoperoxide synthase-2 (cyclooxygenase-2) by aspirin. (1994). https://pubmed.ncbi.nlm.nih.gov/8175750/ DOI: 10.1016/s0021-9258(17)36820-5
- tissue_or_cell_type
- Recombinant cyclooxygenase
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human cyclooxygenase-1 and -2 expressed in cos-1 cells treated with aspirin and with carbon-14 labelled aspirin, with a mutant series at Ser-516 · source_derived_draft · unverified_draft
### asa-ser516-is-the-site When microsomal human cyclooxygenase-2 was incubated with acetyl-carbon-14 labelled aspirin the enzyme was acetylated, while an S516A mutant which retains enzyme activity was not acetylated, indicating that Ser-516 is the site of aspirin acetylation and is homologous to the active site serine of cyclooxygenase-1; an S516N mutant was catalytically active whereas an S516Q mutant lacked cyclooxygenase but retained peroxidase activity, and because in cyclooxygenase-1 the smaller asparagine substitution suffices to eliminate cyclooxygenase activity the active site of cyclooxygenase-2 is slightly larger. Condition category: normal nutrient_topic: Aspirin research collection; topical membership is not evidence of a direct clinical effect, and aspirin is recorded separately from salicylate, the metabolite it becomes. plain_language: The labelled acetyl group lands on one serine, and the second enzyme’s pocket is roomier, which is why the two behave differently. organism: Human enzyme tissue_or_cell_type: Recombinant cyclooxygenase experimental_model: Human cyclooxygenase-1 and -2 expressed in cos-1 cells treated with aspirin and with carbon-14 labelled aspirin, with a mutant series at Ser-516 limitations: Identifies the site by direct labelling and explains the isoform difference by active site volume. Recombinant enzyme in a heterologous cell line. exposure: Aspirin acetylation, with S516A, S516N, S516Q and S516M substitutions evidence_span: {"source_cache": "artifacts/aspirin-research/8175750.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9ba85af90c62b157cf53032375ca703e8b78eff6ddd22ad627bbd7e65965d8e9", "start_char": 0, "end_char": 1786, "text_sha256": "9ba85af90c62b157cf53032375ca703e8b78eff6ddd22ad627bbd7e65965d8e9"} [asa-p8175750] Acetylation of human prostaglandin endoperoxide synthase-2 (cyclooxygenase-2) by aspirin. (1994). https://pubmed.ncbi.nlm.nih.gov/8175750/ DOI: 10.1016/s0021-9258(17)36820-5
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.