{"id":"6c6dcf7c-1363-59d5-9ee9-5d679627246c","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-prolyl-uncoupled-consumption","predicate":"consumes-in-uncoupled-cycles","statement":"Chick collagen prolyl hydroxylase consumed ascorbate stoichiometrically during uncoupled 2-oxoglutarate decarboxylation in the absence of peptide substrate.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"bae8693e-74ac-5dbe-8204-b6e1e007caaf","mechanism_event_label":"Vitamin C is consumed when this collagen enzyme runs a reaction cycle without hydroxylating its peptide target.","subject":{"id":"00d6f82e-4f52-54ea-9121-c4d332c8cd53","slug":"chick-collagen-prolyl-4-hydroxylase","display_name":"Chick collagen prolyl 4-hydroxylase preparation","entity_type_key":"protein_complex"},"object":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"bae8693e-74ac-5dbe-8204-b6e1e007caaf","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-prolyl-uncoupled-consumption-event","event_type":"biochemical_relationship","label":"Vitamin C is consumed when this collagen enzyme runs a reaction cycle without hydroxylating its peptide target.","description":"Chick collagen prolyl hydroxylase consumed ascorbate stoichiometrically during uncoupled 2-oxoglutarate decarboxylation in the absence of peptide substrate.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"00d6f82e-4f52-54ea-9121-c4d332c8cd53","slug":"chick-collagen-prolyl-4-hydroxylase","display_name":"Chick collagen prolyl 4-hydroxylase preparation","entity_type_key":"protein_complex"},"role":"enzyme","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":"consumed-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":"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":3,"notes":""},{"entity":{"id":"899c7ab0-6f81-5b38-a6bd-fbb33d66ac8d","slug":"oxygen","display_name":"Molecular oxygen","entity_type_key":"small_molecule"},"role":"cosubstrate","stoichiometry":null,"state_label":"","sequence_order":4,"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 prolyl and partially purified lysyl collagen hydroxylases","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Peptide substrate present or absent; uncoupled 2-oxoglutarate decarboxylation assays.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Substrate-free enzyme reaction; frequency and quantitative vitamin C cost of uncoupled cycles in human tissues were not measured.","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":"Vitamin C is consumed when this collagen enzyme runs a reaction cycle without hydroxylating its peptide target.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[myllyla1984] Ascorbate is consumed stoichiometrically in the uncoupled reactions catalyzed by prolyl 4-hydroxylase and lysyl hydroxylase. (1984). https://pubmed.ncbi.nlm.nih.gov/6325436/ DOI: 10.1016/s0021-9258(18)91023-9","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Chick embryo enzyme preparations","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"f4e69c42-28f9-5821-9a2b-ef6ae2e3a1ae","evidence_kind":"source_excerpt","locator":"Lines 598-609","start_line":598,"end_line":609,"excerpt":"### vc-enzyme-prolyl-uncoupled-consumption\nChick collagen prolyl hydroxylase consumed ascorbate stoichiometrically during uncoupled 2-oxoglutarate decarboxylation in the absence of peptide substrate.\nCondition category: normal\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Vitamin C is consumed when this collagen enzyme runs a reaction cycle without hydroxylating its peptide target.\norganism: Gallus gallus\ntissue_or_cell_type: Chick embryo enzyme preparations\nexperimental_model: Purified chick prolyl and partially purified lysyl collagen hydroxylases\nlimitations: Substrate-free enzyme reaction; frequency and quantitative vitamin C cost of uncoupled cycles in human tissues were not measured.\ncross_nutrient: Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.\nexposure: Peptide substrate present or absent; uncoupled 2-oxoglutarate decarboxylation assays.\n[myllyla1984] Ascorbate is consumed stoichiometrically in the uncoupled reactions catalyzed by prolyl 4-hydroxylase and lysyl hydroxylase. (1984). https://pubmed.ncbi.nlm.nih.gov/6325436/ DOI: 10.1016/s0021-9258(18)91023-9","model_system":"Purified chick prolyl and partially purified lysyl collagen hydroxylases","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [myllyla1984] Ascorbate is consumed stoichiometrically in the uncoupled reactions catalyzed by prolyl 4-hydroxylase and lysyl hydroxylase. (1984). https://pubmed.ncbi.nlm.nih.gov/6325436/ DOI: 10.1016/s0021-9258(18)91023-9","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"fa811221-13bd-5c10-adc1-eaf097c7703c","stable_key":"import-cb568d28-484a-5c2e-9fcc-2d780358e514","title":"Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"b7fd83f956abb81855f2ea23199ba14e465cd91f4a2ac560277ec21ddafd7bfc","revision_id":"6cde9bbb-d712-5746-82a6-85b144253efa","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}