{"id":"40710303-3361-501a-9267-75a4064a9bb6","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-free-iron-not-replacement","predicate":"does-not-reactivate-under-2og","statement":"With 2-oxoglutarate present, added Fe(II) did not partly reactivate the inactivated chick prolyl hydroxylase as ascorbate did; reduction by Fe(II) was possible in the absence of 2-oxoglutarate.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"c29ddc9b-849f-56ed-ad22-290bc84591ea","mechanism_event_label":"Adding free iron did not substitute for vitamin C under the tested enzyme conditions.","subject":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"object":{"id":"04d3ed6f-497b-58f0-ac99-c67943db2d9c","slug":"chick-p4h-ferric-state","display_name":"Chick collagen prolyl 4-hydroxylase with oxidized enzyme-bound iron","entity_type_key":"protein_state"},"evidence_count":1,"mechanism_event":{"id":"c29ddc9b-849f-56ed-ad22-290bc84591ea","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-free-iron-not-replacement-event","event_type":"biochemical_relationship","label":"Adding free iron did not substitute for vitamin C under the tested enzyme conditions.","description":"With 2-oxoglutarate present, added Fe(II) did not partly reactivate the inactivated chick prolyl hydroxylase as ascorbate did; reduction by Fe(II) was possible in the absence of 2-oxoglutarate.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"role":"enzyme-metal-cofactor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"role":"supporting-reductant","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"628ddc2d-e4d9-59c7-ae76-0c0cab80a6b1","slug":"2-oxoglutarate","display_name":"2-Oxoglutarate","entity_type_key":"small_molecule"},"role":"cosubstrate","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"04d3ed6f-497b-58f0-ac99-c67943db2d9c","slug":"chick-p4h-ferric-state","display_name":"Chick collagen prolyl 4-hydroxylase with oxidized enzyme-bound iron","entity_type_key":"protein_state"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified chick collagen prolyl hydroxylase, EPR and activity measurements","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"400 micromolar 2-oxoglutarate; enzyme inactivation within 1 minute without ascorbate; 30-second EPR incubation at 37 C.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Context depends on 2-oxoglutarate; this is not a clinical comparison of iron and vitamin C supplements.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin C research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Gallus gallus","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Adding free iron did not substitute for vitamin C under the tested enzyme conditions.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[dejong1982] Prolyl 4-hydroxylase activity in relation to the oxidation state of enzyme-bound iron. The role of ascorbate in peptidyl proline hydroxylation. (1982). https://pubmed.ncbi.nlm.nih.gov/6285984/ DOI: 10.1016/0167-4838(82)90162-5","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Chick embryo enzyme preparation","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"7f43c993-f0e3-5350-ad41-9530a28f3fc8","evidence_kind":"source_excerpt","locator":"Lines 637-648","start_line":637,"end_line":648,"excerpt":"### vc-enzyme-free-iron-not-replacement\nWith 2-oxoglutarate present, added Fe(II) did not partly reactivate the inactivated chick prolyl hydroxylase as ascorbate did; reduction by Fe(II) was possible in the absence of 2-oxoglutarate.\nCondition category: normal\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Adding free iron did not substitute for vitamin C under the tested enzyme conditions.\norganism: Gallus gallus\ntissue_or_cell_type: Chick embryo enzyme preparation\nexperimental_model: Purified chick collagen prolyl hydroxylase, EPR and activity measurements\nlimitations: Context depends on 2-oxoglutarate; this is not a clinical comparison of iron and vitamin C supplements.\ncross_nutrient: Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.\nexposure: 400 micromolar 2-oxoglutarate; enzyme inactivation within 1 minute without ascorbate; 30-second EPR incubation at 37 C.\n[dejong1982] Prolyl 4-hydroxylase activity in relation to the oxidation state of enzyme-bound iron. The role of ascorbate in peptidyl proline hydroxylation. (1982). https://pubmed.ncbi.nlm.nih.gov/6285984/ DOI: 10.1016/0167-4838(82)90162-5","model_system":"Purified chick collagen prolyl hydroxylase, EPR and activity measurements","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [dejong1982] Prolyl 4-hydroxylase activity in relation to the oxidation state of enzyme-bound iron. The role of ascorbate in peptidyl proline hydroxylation. 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