{"id":"bb555f4c-61a8-5780-8653-ac3e3d3fc8f2","stable_key":"ae1ed35d-8ce7-5936-9067-a641374bbf79:carnosine-oxo-product","predicate":"oxidized_to","statement":"Oxidation of carnosine produced 2-oxo-carnosine; mechanistic analysis supported imidazole-radical formation followed by oxygen addition.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"c8015777-d534-561f-8f25-a969eb441fde","mechanism_event_label":"An oxidation product can retain biological activity.","subject":{"id":"9998eb9b-0d09-58c9-885b-a442477dec8d","slug":"carnosine","display_name":"L-Carnosine / beta-alanyl-L-histidine","entity_type_key":"small_molecule"},"object":{"id":"3ac09be9-1667-59a0-aaaa-ddb68c60be24","slug":"2-oxo-carnosine","display_name":"2-Oxo-carnosine","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"c8015777-d534-561f-8f25-a969eb441fde","stable_key":"ae1ed35d-8ce7-5936-9067-a641374bbf79:carnosine-oxo-product-event","event_type":"observed_relationship","label":"An oxidation product can retain biological activity.","description":"Oxidation of carnosine produced 2-oxo-carnosine; mechanistic analysis supported imidazole-radical formation followed by oxygen addition.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"9998eb9b-0d09-58c9-885b-a442477dec8d","slug":"carnosine","display_name":"L-Carnosine / beta-alanyl-L-histidine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"3ac09be9-1667-59a0-aaaa-ddb68c60be24","slug":"2-oxo-carnosine","display_name":"2-Oxo-carnosine","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"2a870bb5-05a0-5e51-a70c-a9a843a8b571","slug":"copper-ii","display_name":"Copper(II) ion","entity_type_key":"ion"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Chemical analysis, mouse tissues and human neuroblastoma cells.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Product formation is distinct from simple removal of oxidants.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Carnosine collection; isomer, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"carnosine","display_name":"L-Carnosine / beta-alanyl-L-histidine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"An oxidation product can retain biological activity.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"2-Oxo-histidine-containing dipeptides are functional oxidation products. · 2019 · https://pubmed.ncbi.nlm.nih.gov/30504220/ · DOI 10.1074/jbc.RA118.006111","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"a2c427a9-192e-511a-9ecc-80fb651b823a","evidence_kind":"source_excerpt","locator":"Lines 340-346","start_line":340,"end_line":346,"excerpt":"## carnosine-oxo-product\nAn oxidation product can retain biological activity.\nOxidation of carnosine produced 2-oxo-carnosine; mechanistic analysis supported imidazole-radical formation followed by oxygen addition.\nModel: Chemical analysis, mouse tissues and human neuroblastoma cells.\nLimitations: Product formation is distinct from simple removal of oxidants.\nEvidence access: Primary abstract\n2-Oxo-histidine-containing dipeptides are functional oxidation products. · 2019 · https://pubmed.ncbi.nlm.nih.gov/30504220/ · DOI 10.1074/jbc.RA118.006111","model_system":"Chemical analysis, mouse tissues and human neuroblastoma cells.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"87dc5af2-4eb6-5980-b7e0-bf3697b1156e","stable_key":"import-ae1ed35d-8ce7-5936-9067-a641374bbf79","title":"Carnosine: synthesis, transport, carbonyl chemistry and nutrient interactions (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary-abstract references and experimental limitations individually identified. 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