{"id":"644ebd30-f2d2-541e-879d-8422610dbba7","stable_key":"335be270-ea4a-5c8e-ad04-964fd22a439e:vanadium-ascorbate-reduction","predicate":"reduces_vanadate_to","statement":"Ascorbate generated V(IV) from vanadate in phosphate buffer at pH 7.4, but not comparably in water or the tested cacodylate buffer.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"247bcfd2-7b1b-54e3-a5df-7f52ac2098c0","mechanism_event_label":"Vitamin C and phosphate together changed vanadium’s oxidation state in this assay.","subject":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"object":{"id":"656eb223-933b-5a40-b70c-0d77537fe717","slug":"vanadyl-iv","display_name":"Oxovanadium(IV) / vanadyl","entity_type_key":"ion"},"evidence_count":1,"mechanism_event":{"id":"247bcfd2-7b1b-54e3-a5df-7f52ac2098c0","stable_key":"335be270-ea4a-5c8e-ad04-964fd22a439e:vanadium-ascorbate-reduction-event","event_type":"observed_relationship","label":"Vitamin C and phosphate together changed vanadium’s oxidation state in this assay.","description":"Ascorbate generated V(IV) from vanadate in phosphate buffer at pH 7.4, but not comparably in water or the tested cacodylate buffer.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"656eb223-933b-5a40-b70c-0d77537fe717","slug":"vanadyl-iv","display_name":"Oxovanadium(IV) / vanadyl","entity_type_key":"ion"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"c5cbad45-22c6-594b-ab6b-71880dab1b24","slug":"vanadium","display_name":"Vanadium","entity_type_key":"nutrient_element"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"bef86a6e-28a0-5df9-9306-3f05991aa159","slug":"vanadate-v","display_name":"Vanadate(V), protonation/speciation dependent","entity_type_key":"chemical_species"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"b28dfc54-a5ef-5f9e-ac1f-890b68e58dc3","slug":"inorganic-phosphate","display_name":"Inorganic phosphate","entity_type_key":"chemical_species"},"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":"ESR and spin-trapping chemistry; cell-free solutions.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Buffer-dependent chemistry does not establish a human depletion rate or clinical interaction.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vanadium collection; molecular form, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vanadium","display_name":"Vanadium","entity_type_key":"nutrient_element"}},{"dimension":"plain_language","value_text":"Vitamin C and phosphate together changed vanadium’s oxidation state in this assay.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"One-electron reduction of vanadate by ascorbate and related free radical generation at physiological pH. · 1994 · https://pubmed.ncbi.nlm.nih.gov/8051539/ · DOI 10.1016/0162-0134(94)85032-1","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c81afc20-5638-570c-ab5a-4d0f1092644c","evidence_kind":"source_excerpt","locator":"Lines 94-100","start_line":94,"end_line":100,"excerpt":"## vanadium-ascorbate-reduction\nVitamin C and phosphate together changed vanadium’s oxidation state in this assay.\nAscorbate generated V(IV) from vanadate in phosphate buffer at pH 7.4, but not comparably in water or the tested cacodylate buffer.\nModel: ESR and spin-trapping chemistry; cell-free solutions.\nLimitations: Buffer-dependent chemistry does not establish a human depletion rate or clinical interaction.\nEvidence access: Primary abstract\nOne-electron reduction of vanadate by ascorbate and related free radical generation at physiological pH. · 1994 · https://pubmed.ncbi.nlm.nih.gov/8051539/ · DOI 10.1016/0162-0134(94)85032-1","model_system":"ESR and spin-trapping chemistry; cell-free solutions.","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":"e4d5d0ba-529b-540f-96ed-e719d116ccfd","stable_key":"import-335be270-ea4a-5c8e-ad04-964fd22a439e","title":"Vanadium: speciation, phosphate-sensitive enzymes and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text.","file_path":"","sha256":"d36b30d972e756ca4d19b66f976980e206c65025bd4bbf4c127c17320bd019c2","revision_id":"70d42967-8032-5627-8670-f59841735e89","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}