{"id":"f521ba0e-8fd7-5ee7-90eb-7362ce364cce","stable_key":"f8641d02-8413-5bd8-92e9-62ad49286e81:asa-methionine-mimics-acetyl","predicate":"produces","statement":"While prostaglandin synthesis by both isoforms is inhibited by aspirin, 15-R-hydroxyeicosatetraenoic acid synthesis by cyclooxygenase-2 but not cyclooxygenase-1 is stimulated by preincubation with aspirin, and enzyme activity and inhibitor sensitivity studies of mutants provide evidence that Ser516 is the aspirin acetylation site of human cyclooxygenase-2 and that substitution of a methionine at this position can mimic the effects of aspirin acetylation on enzyme activity.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"d6f685d9-1cd3-5919-aa62-cd58b7ab2487","mechanism_event_label":"Putting a methionine where the acetyl group would go reproduces the switch without any drug.","subject":{"id":"11741820-6c04-50a2-bed5-2926a56bb930","slug":"cox2-s516m","display_name":"Cyclooxygenase-2 with methionine substituted at position 516","entity_type_key":"protein_state"},"object":{"id":"a8fa3506-620f-5c71-a0f1-226962e93b69","slug":"15r-hete","display_name":"15(R)-hydroxyeicosatetraenoic acid","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"d6f685d9-1cd3-5919-aa62-cd58b7ab2487","stable_key":"f8641d02-8413-5bd8-92e9-62ad49286e81:asa-methionine-mimics-acetyl-event","event_type":"biochemical_relationship","label":"Putting a methionine where the acetyl group would go reproduces the switch without any drug.","description":"While prostaglandin synthesis by both isoforms is inhibited by aspirin, 15-R-hydroxyeicosatetraenoic acid synthesis by cyclooxygenase-2 but not cyclooxygenase-1 is stimulated by preincubation with aspirin, and enzyme activity and inhibitor sensitivity studies of mutants provide evidence that Ser516 is the aspirin acetylation site of human cyclooxygenase-2 and that substitution of a methionine at this position can mimic the effects of aspirin acetylation on enzyme activity.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"48cd6cab-de3d-53bd-a690-a1f9e5b78a7d","slug":"cox2-ser516","display_name":"Serine 516 of cyclooxygenase-2","entity_type_key":"protein_state"},"role":"substituted_residue","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"cda05399-1c07-5459-b8e2-0edcf5066e94","slug":"acetylated-cox2","display_name":"Aspirin-acetylated cyclooxygenase-2","entity_type_key":"protein_state"},"role":"mimicked_state","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"11741820-6c04-50a2-bed5-2926a56bb930","slug":"cox2-s516m","display_name":"Cyclooxygenase-2 with methionine substituted at position 516","entity_type_key":"protein_state"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"a8fa3506-620f-5c71-a0f1-226962e93b69","slug":"15r-hete","display_name":"15(R)-hydroxyeicosatetraenoic acid","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/aspirin-research/8143845.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"ddf63e3296e1f35a88de948bc23fda6654c2eaf247b1d6d3987e95989c966f93\", \"start_char\": 0, \"end_char\": 903, \"text_sha256\": \"ddf63e3296e1f35a88de948bc23fda6654c2eaf247b1d6d3987e95989c966f93\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Mutants of the putative acetylation site of human cyclooxygenase-2 expressed in COS-7 cells by recombinant vaccinia virus","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Substitution at Ser516, including methionine, compared with aspirin preincubation","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"A second, independent identification of the same residue with a substitution that mimics the acetylated state. Vaccinia-driven expression in a heterologous line.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Aspirin research collection; topical membership is not evidence of a direct clinical effect, and aspirin is recorded separately from salicylate, the metabolite it becomes.","comparator":null,"unit":null,"notes":"","entity":{"slug":"aspirin","display_name":"Aspirin / acetylsalicylic acid","entity_type_key":"drug"}},{"dimension":"organism","value_text":"Human enzyme","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Putting a methionine where the acetyl group would go reproduces the switch without any drug.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[asa-p8143845] Mutation of serine-516 in human prostaglandin G/H synthase-2 to methionine or aspirin acetylation of this residue stimulates 15-R-HETE synthesis. (1994). https://pubmed.ncbi.nlm.nih.gov/8143845/ DOI: 10.1016/0014-5793(94)80579-2","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Recombinant cyclooxygenase-2","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"e5b3d4ee-df4a-5292-a51c-0f60fa18672d","evidence_kind":"source_excerpt","locator":"Lines 234-245","start_line":234,"end_line":245,"excerpt":"### asa-methionine-mimics-acetyl\nWhile prostaglandin synthesis by both isoforms is inhibited by aspirin, 15-R-hydroxyeicosatetraenoic acid synthesis by cyclooxygenase-2 but not cyclooxygenase-1 is stimulated by preincubation with aspirin, and enzyme activity and inhibitor sensitivity studies of mutants provide evidence that Ser516 is the aspirin acetylation site of human cyclooxygenase-2 and that substitution of a methionine at this position can mimic the effects of aspirin acetylation on enzyme activity.\nCondition category: normal\nnutrient_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.\nplain_language: Putting a methionine where the acetyl group would go reproduces the switch without any drug.\norganism: Human enzyme\ntissue_or_cell_type: Recombinant cyclooxygenase-2\nexperimental_model: Mutants of the putative acetylation site of human cyclooxygenase-2 expressed in COS-7 cells by recombinant vaccinia virus\nlimitations: A second, independent identification of the same residue with a substitution that mimics the acetylated state. Vaccinia-driven expression in a heterologous line.\nexposure: Substitution at Ser516, including methionine, compared with aspirin preincubation\nevidence_span: {\"source_cache\": \"artifacts/aspirin-research/8143845.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"ddf63e3296e1f35a88de948bc23fda6654c2eaf247b1d6d3987e95989c966f93\", \"start_char\": 0, \"end_char\": 903, \"text_sha256\": \"ddf63e3296e1f35a88de948bc23fda6654c2eaf247b1d6d3987e95989c966f93\"}\n[asa-p8143845] Mutation of serine-516 in human prostaglandin G/H synthase-2 to methionine or aspirin acetylation of this residue stimulates 15-R-HETE synthesis. (1994). https://pubmed.ncbi.nlm.nih.gov/8143845/ DOI: 10.1016/0014-5793(94)80579-2","model_system":"Mutants of the putative acetylation site of human cyclooxygenase-2 expressed in COS-7 cells by recombinant vaccinia virus","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [asa-p8143845] Mutation of serine-516 in human prostaglandin G/H synthase-2 to methionine or aspirin acetylation of this residue stimulates 15-R-HETE synthesis. (1994). https://pubmed.ncbi.nlm.nih.gov/8143845/ DOI: 10.1016/0014-5793(94)80579-2","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"712cf519-cd27-5a8b-9e2f-961a98d7a27e","stable_key":"import-f8641d02-8413-5bd8-92e9-62ad49286e81","title":"Aspirin: the serine it acetylates, the enzyme that acetylation creates, the dose that separates platelet from vessel wall, and the metabolite that is a different drug (2026-09-22)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"93dd4343051c131e40d4fc3c95a978cd65478c13dcdb3f2d42507c49b09cb647","revision_id":"694e8ee7-49ca-5e6c-b58b-8ba8f82c2ad8","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}