{"id":"99a712d6-d427-5780-ad70-f251b6d10f51","stable_key":"335be270-ea4a-5c8e-ad04-964fd22a439e:vanadium-ascorbate-concentration","predicate":"has_concentration_dependent_effect","statement":"Ascorbate initiated NADH oxidation at lower concentrations but inhibited it at higher concentrations in the same chemical system.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"6295395e-0f04-5342-8c2b-310430b2e7df","mechanism_event_label":"The direction of an antioxidant’s effect can depend on concentration.","subject":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"object":{"id":"185d3e29-22ae-5a20-93cc-0c043f38b436","slug":"vanadium-nadh-oxidation","display_name":"NADH oxidation in the vanadium chemical assay","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"6295395e-0f04-5342-8c2b-310430b2e7df","stable_key":"335be270-ea4a-5c8e-ad04-964fd22a439e:vanadium-ascorbate-concentration-event","event_type":"observed_relationship","label":"The direction of an antioxidant’s effect can depend on concentration.","description":"Ascorbate initiated NADH oxidation at lower concentrations but inhibited it at higher concentrations in the same chemical system.","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":"185d3e29-22ae-5a20-93cc-0c043f38b436","slug":"vanadium-nadh-oxidation","display_name":"NADH oxidation in the vanadium chemical assay","entity_type_key":"cellular_process"},"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":""},{"entity":{"id":"9fbf2e03-16a9-5ca7-965c-0bfc07ca24da","slug":"nadh","display_name":"NADH","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Cell-free concentration-response experiments.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Not an established supplement dose-response in humans.","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":"The direction of an antioxidant’s effect can depend on concentration.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Vanadate-mediated oxidation of NADH: description of an in vitro system requiring ascorbate and phosphate. · 1989 · https://pubmed.ncbi.nlm.nih.gov/2735768/ · DOI 10.1016/0003-9861(89)90196-3","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"90927858-f522-5615-a228-6cec8e4abc97","evidence_kind":"source_excerpt","locator":"Lines 134-140","start_line":134,"end_line":140,"excerpt":"## vanadium-ascorbate-concentration\nThe direction of an antioxidant’s effect can depend on concentration.\nAscorbate initiated NADH oxidation at lower concentrations but inhibited it at higher concentrations in the same chemical system.\nModel: Cell-free concentration-response experiments.\nLimitations: Not an established supplement dose-response in humans.\nEvidence access: Primary abstract\nVanadate-mediated oxidation of NADH: description of an in vitro system requiring ascorbate and phosphate. · 1989 · https://pubmed.ncbi.nlm.nih.gov/2735768/ · DOI 10.1016/0003-9861(89)90196-3","model_system":"Cell-free concentration-response experiments.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; 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