{"id":"09538263-4390-573f-a121-c7e515157d03","stable_key":"ea2f0904-ab2c-5d1e-a3d4-3f7ecdd70cd6:caf-xor-product","predicate":"oxidized_to","statement":"Allopurinol specifically and dose-dependently inhibited conversion of caffeine-derived 1-methylxanthine to 1-methyluric acid.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"bb8667c0-f6c8-52af-b861-4497f188ca9d","mechanism_event_label":"A later caffeine metabolite uses the xanthine-oxidoreductase pathway.","subject":{"id":"71ce8da8-6191-5375-b3cd-483d9b736b1c","slug":"1-methylxanthine","display_name":"1-Methylxanthine","entity_type_key":"small_molecule"},"object":{"id":"d23cc5ec-08d0-51b9-bea4-74c5c3d0c357","slug":"1-methyluric-acid","display_name":"1-Methyluric acid","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"bb8667c0-f6c8-52af-b861-4497f188ca9d","stable_key":"ea2f0904-ab2c-5d1e-a3d4-3f7ecdd70cd6:caf-xor-product-event","event_type":"observed_relationship","label":"A later caffeine metabolite uses the xanthine-oxidoreductase pathway.","description":"Allopurinol specifically and dose-dependently inhibited conversion of caffeine-derived 1-methylxanthine to 1-methyluric acid.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"71ce8da8-6191-5375-b3cd-483d9b736b1c","slug":"1-methylxanthine","display_name":"1-Methylxanthine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"d23cc5ec-08d0-51b9-bea4-74c5c3d0c357","slug":"1-methyluric-acid","display_name":"1-Methyluric acid","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"8de34d8a-46dc-512c-a82f-d169747b496e","slug":"xdh","display_name":"Human xanthine oxidoreductase / XDH","entity_type_key":"protein"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"cfa51e26-3627-5a5e-9270-89c53f9db01b","slug":"allopurinol","display_name":"Allopurinol","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"ef028472-7c33-583d-b52e-40676004d370","slug":"caffeine","display_name":"Caffeine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Two healthy nonsmokers; caffeine 5 mg/kg before/during allopurinol 300 or 600 mg/day.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Very small human mechanistic study; not proof that dietary molybdenum controls parent-caffeine clearance.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Caffeine collection; salts, coffee, species and coexposure contexts retain their identities.","comparator":null,"unit":null,"notes":"","entity":{"slug":"caffeine","display_name":"Caffeine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A later caffeine metabolite uses the xanthine-oxidoreductase pathway.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Effect of allopurinol on caffeine disposition in man. · 1986 · https://pubmed.ncbi.nlm.nih.gov/3754760/ · DOI 10.1111/j.1365-2125.1986.tb05222.x","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"1a84c842-2463-56a4-bc42-a414bcafa642","evidence_kind":"source_excerpt","locator":"Lines 228-234","start_line":228,"end_line":234,"excerpt":"## caf-xor-product\nA later caffeine metabolite uses the xanthine-oxidoreductase pathway.\nAllopurinol specifically and dose-dependently inhibited conversion of caffeine-derived 1-methylxanthine to 1-methyluric acid.\nModel: Two healthy nonsmokers; caffeine 5 mg/kg before/during allopurinol 300 or 600 mg/day.\nLimitations: Very small human mechanistic study; not proof that dietary molybdenum controls parent-caffeine clearance.\nEvidence access: Primary abstract\nEffect of allopurinol on caffeine disposition in man. · 1986 · https://pubmed.ncbi.nlm.nih.gov/3754760/ · DOI 10.1111/j.1365-2125.1986.tb05222.x","model_system":"Two healthy nonsmokers; caffeine 5 mg/kg before/during allopurinol 300 or 600 mg/day.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access stated with the claim.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"40a654db-878c-5471-bc6c-88f4f52599c0","stable_key":"import-ea2f0904-ab2c-5d1e-a3d4-3f7ecdd70cd6","title":"Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary-abstract references and experimental limitations individually identified. 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