{"id":"03273c74-2554-52b8-91b9-2909228a66cb","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-fibroblast-prolyl-activity","predicate":"decreases-measured-activity","statement":"In the same human fibroblast culture study, measured collagen prolyl hydroxylase activity decreased after ascorbate treatment even while collagen synthesis increased.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"e14a88bb-b4a7-5608-826f-8a5a10d7f528","mechanism_event_label":"More collagen production did not mean that every hydroxylase activity assay increased.","subject":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"object":{"id":"795ceac7-3661-5b67-afe3-f74812e87721","slug":"human-fibroblast-prolyl-hydroxylase-activity","display_name":"Human fibroblast collagen prolyl hydroxylase activity","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"e14a88bb-b4a7-5608-826f-8a5a10d7f528","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-fibroblast-prolyl-activity-event","event_type":"observed_intervention","label":"More collagen production did not mean that every hydroxylase activity assay increased.","description":"In the same human fibroblast culture study, measured collagen prolyl hydroxylase activity decreased after ascorbate treatment even while collagen synthesis increased.","status":"provisional","compartment":null,"participants":[{"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":0,"notes":""},{"entity":{"id":"795ceac7-3661-5b67-afe3-f74812e87721","slug":"human-fibroblast-prolyl-hydroxylase-activity","display_name":"Human fibroblast collagen prolyl hydroxylase activity","entity_type_key":"cellular_process"},"role":"readout","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"8cfc1234-0fdd-5316-8bca-620c7d8f17d4","slug":"collagen-protein-synthesis","display_name":"Collagen protein synthesis","entity_type_key":"cellular_process"},"role":"parallel-readout","stoichiometry":null,"state_label":"","sequence_order":2,"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":"Cultured human skin fibroblasts","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Prolonged ascorbate exposure versus no added ascorbate; exact culture concentration not verified in accessible abstract.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"A cell-adaptation/activity measurement; not evidence that ascorbate directly inhibits the purified enzyme.","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":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"More collagen production did not mean that every hydroxylase activity assay increased.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[collagen1981] Regulation of collagen synthesis by ascorbic acid. (1981). https://pubmed.ncbi.nlm.nih.gov/6265920/ DOI: 10.1073/pnas.78.5.2879","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Skin fibroblasts","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"a8eddc1d-8a8b-5865-a4cc-818f21c17eb6","evidence_kind":"source_excerpt","locator":"Lines 676-687","start_line":676,"end_line":687,"excerpt":"### vc-enzyme-fibroblast-prolyl-activity\nIn the same human fibroblast culture study, measured collagen prolyl hydroxylase activity decreased after ascorbate treatment even while collagen synthesis increased.\nCondition category: normal\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: More collagen production did not mean that every hydroxylase activity assay increased.\norganism: Homo sapiens\ntissue_or_cell_type: Skin fibroblasts\nexperimental_model: Cultured human skin fibroblasts\nlimitations: A cell-adaptation/activity measurement; not evidence that ascorbate directly inhibits the purified enzyme.\ncross_nutrient: Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.\nexposure: Prolonged ascorbate exposure versus no added ascorbate; exact culture concentration not verified in accessible abstract.\n[collagen1981] Regulation of collagen synthesis by ascorbic acid. (1981). https://pubmed.ncbi.nlm.nih.gov/6265920/ DOI: 10.1073/pnas.78.5.2879","model_system":"Cultured human skin fibroblasts","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [collagen1981] Regulation of collagen synthesis by ascorbic acid. (1981). https://pubmed.ncbi.nlm.nih.gov/6265920/ DOI: 10.1073/pnas.78.5.2879","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. 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