{"id":"ea589e7d-8479-5fd6-a07d-e6804109e6c3","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-mmachc-free-flavin-decyanation","predicate":"flavin-dependently-decyanates","statement":"Human MMACHC residues 1–244 supported cyanocobalamin decyanation with FMN or FAD plus NADPH, without a separately supplied flavoprotein reductase; reduced FMN also supported the reaction.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"8639b65d-f3ff-52a9-a890-32e5b30eb0e1","mechanism_event_label":"A truncated B12-processing protein could use supplied flavins to carry out this reaction.","subject":{"id":"57e22da4-0564-5726-83c1-fd710174f731","slug":"mmachc-delta-c38","display_name":"Human MMACHC deltaC38","entity_type_key":"protein_state"},"object":{"id":"4cb4dfbc-6cd9-5bd5-98dc-d0a8fb6cfee4","slug":"cyanocobalamin","display_name":"Cyanocobalamin","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"8639b65d-f3ff-52a9-a890-32e5b30eb0e1","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-mmachc-free-flavin-decyanation-event","event_type":"biochemical_relationship","label":"A truncated B12-processing protein could use supplied flavins to carry out this reaction.","description":"Human MMACHC residues 1–244 supported cyanocobalamin decyanation with FMN or FAD plus NADPH, without a separately supplied flavoprotein reductase; 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unverified.","entity":null}],"evidence":[{"id":"99e824c0-ebe8-5d72-a271-e06d342f749d","evidence_kind":"source_excerpt","locator":"Lines 753-765","start_line":753,"end_line":765,"excerpt":"### b12-mmachc-free-flavin-decyanation\nHuman MMACHC residues 1–244 supported cyanocobalamin decyanation with FMN or FAD plus NADPH, without a separately supplied flavoprotein reductase; reduced FMN also supported the reaction.\nCondition category: machinery_impairment\nnutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A truncated B12-processing protein could use supplied flavins to carry out this reaction.\norganism: Homo sapiens\ntissue_or_cell_type: Cell-free assay\nexperimental_model: Recombinant human MMACHC deltaC38 biochemical assay\nlimitations: Engineered truncation and reconstitution; does not establish that riboflavin supplementation rescues MMACHC defects.\nexposure: 30–40 micromolar FMN/FAD with 200 micromolar NADPH, or photoreduced FMN\ncross_nutrient: true\nevidence_location: Experimental procedures and Results: CblC Has a Flavin Reductase Fold; Figure 1c\n[koutmos-2011-flavin] Structural Basis of Multifunctionality in a Vitamin B12-processing Enzyme (2011). https://pubmed.ncbi.nlm.nih.gov/21697092/ DOI: 10.1074/jbc.M111.261370","model_system":"Recombinant human MMACHC deltaC38 biochemical assay","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. 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