{"id":"08794f7a-9ac4-5226-b793-25599085a276","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-mtrr-dual-flavins","predicate":"binds","statement":"Purified recombinant human MTRR contained equimolar FAD and FMN, identifying two distinct flavin cofactors in the same reductase.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"7f017b73-2d5f-5220-87de-4e3bd19457d5","mechanism_event_label":"MTRR uses both B2-derived cofactors.","subject":{"id":"a0be0dca-5f6e-54a8-b760-e59a0658207d","slug":"mtrr","display_name":"Methionine synthase reductase / MTRR","entity_type_key":"protein"},"object":{"id":"e2cd7179-f218-54e8-9ce9-7a836ae35fac","slug":"fad","display_name":"FAD","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"7f017b73-2d5f-5220-87de-4e3bd19457d5","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-mtrr-dual-flavins-event","event_type":"biochemical_relationship","label":"MTRR uses both B2-derived cofactors.","description":"Purified recombinant human MTRR contained equimolar FAD and FMN, identifying two distinct flavin cofactors in the same reductase.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"e2cd7179-f218-54e8-9ce9-7a836ae35fac","slug":"fad","display_name":"FAD","entity_type_key":"small_molecule"},"role":"cofactor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"d3eacf85-1a35-546d-bd30-161474dd9691","slug":"fmn","display_name":"Flavin mononucleotide","entity_type_key":"small_molecule"},"role":"cofactor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"a0be0dca-5f6e-54a8-b760-e59a0658207d","slug":"mtrr","display_name":"Methionine synthase reductase / MTRR","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"B2-derived flavins form part of the B12-reactivation machinery.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_location","value_text":"Abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human MTRR purification, flavin analysis, NADPH spectroscopy and methionine-synthase reconstitution.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Purified-enzyme assay","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Biochemical evidence does not establish a dietary threshold or supplementation benefit.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Riboflavin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"riboflavin","display_name":"Riboflavin (vitamin B2)","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"MTRR uses both B2-derived cofactors.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[olteanu2001] Human methionine synthase reductase, a soluble P-450 reductase-like dual flavoprotein, is sufficient for NADPH-dependent methionine synthase activation. (2001). https://pubmed.ncbi.nlm.nih.gov/11466310/ DOI: 10.1074/jbc.m103707200","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified recombinant enzyme; no intact tissue","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"e020c51d-9cf0-5aaa-a7d8-790918c5ae30","evidence_kind":"source_excerpt","locator":"Lines 1094-1106","start_line":1094,"end_line":1106,"excerpt":"### b2-mtrr-dual-flavins\nPurified recombinant human MTRR contained equimolar FAD and FMN, identifying two distinct flavin cofactors in the same reductase.\nCondition category: normal\nnutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: MTRR uses both B2-derived cofactors.\norganism: Homo sapiens\ntissue_or_cell_type: Purified recombinant enzyme; no intact tissue\nexperimental_model: Recombinant human MTRR purification, flavin analysis, NADPH spectroscopy and methionine-synthase reconstitution.\nlimitations: Biochemical evidence does not establish a dietary threshold or supplementation benefit.\nexposure: Purified-enzyme assay\ncross_nutrient: B2-derived flavins form part of the B12-reactivation machinery.\nevidence_location: Abstract\n[olteanu2001] Human methionine synthase reductase, a soluble P-450 reductase-like dual flavoprotein, is sufficient for NADPH-dependent methionine synthase activation. (2001). https://pubmed.ncbi.nlm.nih.gov/11466310/ DOI: 10.1074/jbc.m103707200","model_system":"Recombinant human MTRR purification, flavin analysis, NADPH spectroscopy and methionine-synthase reconstitution.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [olteanu2001] Human methionine synthase reductase, a soluble P-450 reductase-like dual flavoprotein, is sufficient for NADPH-dependent methionine synthase activation. (2001). https://pubmed.ncbi.nlm.nih.gov/11466310/ DOI: 10.1074/jbc.m103707200","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"4f7c9578-82bf-5e2d-b5c4-72a79fb4f6af","stable_key":"import-548ab9d6-3a9b-5bed-879c-17d03813b636","title":"Riboflavin: 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":"680cb6bc8249877f2410f551807f10d390fdd719014137d7414ba3420e29228d","revision_id":"7a61e299-908d-5372-860b-99ed190f9d7a","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}