{"id":"de4d1ecd-f9e9-5888-ae42-9155392da12e","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-dbh-copper-reduction","predicate":"generates-reduced-enzyme-state","statement":"Ascorbate reduced enzyme-bound copper in purified bovine dopamine beta-hydroxylase from Cu(II) to Cu(I), as examined by X-ray absorption spectroscopy.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"29f3ef77-5207-5c70-b6fa-f31b6079dac9","mechanism_event_label":"Vitamin C supplies reducing power to copper held inside this neurotransmitter enzyme.","subject":{"id":"38d0c4d9-53d1-5239-bfe3-c1b5e9b79085","slug":"ascorbate","display_name":"L-Ascorbate","entity_type_key":"small_molecule"},"object":{"id":"07dd98e9-f18a-5187-83bb-d2f1f10605f4","slug":"bovine-dbh-cu-i-state","display_name":"Ascorbate-reduced bovine dopamine beta-hydroxylase","entity_type_key":"protein_state"},"evidence_count":1,"mechanism_event":{"id":"29f3ef77-5207-5c70-b6fa-f31b6079dac9","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-dbh-copper-reduction-event","event_type":"biochemical_relationship","label":"Vitamin C supplies reducing power to copper held inside this neurotransmitter enzyme.","description":"Ascorbate reduced enzyme-bound copper in purified bovine dopamine beta-hydroxylase from Cu(II) to Cu(I), as examined by X-ray absorption spectroscopy.","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":"78df2518-5479-5765-98cd-56c63f91d2a4","slug":"bovine-dbh","display_name":"Bovine dopamine beta-hydroxylase","entity_type_key":"protein"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"2a870bb5-05a0-5e51-a70c-a9a843a8b571","slug":"copper-ii","display_name":"Copper(II) ion","entity_type_key":"ion"},"role":"oxidized-enzyme-metal","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"162020b5-1fa5-526e-8405-452891245722","slug":"copper-i","display_name":"Copper(I) ion","entity_type_key":"ion"},"role":"reduced-enzyme-metal","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"07dd98e9-f18a-5187-83bb-d2f1f10605f4","slug":"bovine-dbh-cu-i-state","display_name":"Ascorbate-reduced bovine dopamine beta-hydroxylase","entity_type_key":"protein_state"},"role":"product-state","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":"Bovine dopamine beta-hydroxylase X-ray absorption and EXAFS","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Ascorbate reduction of purified Cu(II)-DBH to Cu(I)-DBH.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Purified bovine enzyme, not a dietary copper-status measurement. Scott 1988 and Blumberg 1989 disagree on the detailed coordination change and heavy-atom ligation; this record retains only the shared Cu(II)-to-Cu(I) redox conclusion.","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":"Bos taurus","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Vitamin C supplies reducing power to copper held inside this neurotransmitter enzyme.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[scott1988] The copper sites of dopamine beta-hydroxylase: an X-ray absorption spectroscopic study. (1988). https://pubmed.ncbi.nlm.nih.gov/3179263/ DOI: 10.1021/bi00415a005\n[blumberg1989] X-ray absorption spectroscopic study of the active copper sites in dopamine beta-hydroxylase. (1989). https://pubmed.ncbi.nlm.nih.gov/2703478/ DOI: 10.1016/s0021-9258(18)83307-5","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Adrenal-medullary enzyme preparation","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"0b9c1f1c-1150-5ac8-8a45-e0f8eab1a15f","evidence_kind":"source_excerpt","locator":"Lines 793-805","start_line":793,"end_line":805,"excerpt":"### vc-enzyme-dbh-copper-reduction\nAscorbate reduced enzyme-bound copper in purified bovine dopamine beta-hydroxylase from Cu(II) to Cu(I), as examined by X-ray absorption spectroscopy.\nCondition category: normal\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Vitamin C supplies reducing power to copper held inside this neurotransmitter enzyme.\norganism: Bos taurus\ntissue_or_cell_type: Adrenal-medullary enzyme preparation\nexperimental_model: Bovine dopamine beta-hydroxylase X-ray absorption and EXAFS\nlimitations: Purified bovine enzyme, not a dietary copper-status measurement. Scott 1988 and Blumberg 1989 disagree on the detailed coordination change and heavy-atom ligation; this record retains only the shared Cu(II)-to-Cu(I) redox conclusion.\ncross_nutrient: Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.\nexposure: Ascorbate reduction of purified Cu(II)-DBH to Cu(I)-DBH.\n[scott1988] The copper sites of dopamine beta-hydroxylase: an X-ray absorption spectroscopic study. (1988). https://pubmed.ncbi.nlm.nih.gov/3179263/ DOI: 10.1021/bi00415a005\n[blumberg1989] X-ray absorption spectroscopic study of the active copper sites in dopamine beta-hydroxylase. (1989). https://pubmed.ncbi.nlm.nih.gov/2703478/ DOI: 10.1016/s0021-9258(18)83307-5","model_system":"Bovine dopamine beta-hydroxylase X-ray absorption and EXAFS","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [scott1988] The copper sites of dopamine beta-hydroxylase: an X-ray absorption spectroscopic study. (1988). https://pubmed.ncbi.nlm.nih.gov/3179263/ DOI: 10.1021/bi00415a005; [blumberg1989] X-ray absorption spectroscopic study of the active copper sites in dopamine beta-hydroxylase. (1989). https://pubmed.ncbi.nlm.nih.gov/2703478/ DOI: 10.1016/s0021-9258(18)83307-5","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}