{"id":"732bbdf6-fc34-58c8-9923-fd4e551a7c3b","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-met-mcad-etf-electron-transfer","predicate":"transfers-electrons-to","statement":"Human MCAD and ETF form an electron-transfer complex in which a recognition loop anchors binding while the ETF FAD domain samples electron-transfer-compatible conformations.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"70dd7f19-b252-5f76-9716-eccba7d0aac9","mechanism_event_label":"Fatty-acid oxidation hands electrons from MCAD to a distinct ETF carrier.","subject":{"id":"22d58f68-4758-52a6-9127-70a32ca264cc","slug":"acadm","display_name":"Human medium-chain acyl-CoA dehydrogenase / ACADM","entity_type_key":"protein"},"object":{"id":"8851f7f6-96e8-534d-ba5f-d3eab68eb3db","slug":"electron-transfer-flavoprotein","display_name":"Human electron transfer flavoprotein / ETF","entity_type_key":"protein_complex"},"evidence_count":1,"mechanism_event":{"id":"70dd7f19-b252-5f76-9716-eccba7d0aac9","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-met-mcad-etf-electron-transfer-event","event_type":"biochemical_relationship","label":"Fatty-acid oxidation hands electrons from MCAD to a distinct ETF carrier.","description":"Human MCAD and ETF form an electron-transfer complex in which a recognition loop anchors binding while the ETF FAD domain samples electron-transfer-compatible conformations.","status":"provisional","compartment":{"slug":"mitochondria","display_name":"Mitochondria"},"participants":[{"entity":{"id":"e2cd7179-f218-54e8-9ce9-7a836ae35fac","slug":"fad","display_name":"FAD","entity_type_key":"small_molecule"},"role":"mobile redox cofactor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"949ab4a0-5377-5106-9ca4-6077d83bf31b","slug":"etfa","display_name":"Human electron transfer flavoprotein alpha / ETFA","entity_type_key":"protein"},"role":"ETF alpha subunit","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"2c78956f-60c1-5351-91eb-67abc16b46a2","slug":"etfb","display_name":"Human electron transfer flavoprotein beta / ETFB","entity_type_key":"protein"},"role":"ETF beta subunit","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"22d58f68-4758-52a6-9127-70a32ca264cc","slug":"acadm","display_name":"Human medium-chain acyl-CoA dehydrogenase / ACADM","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"8851f7f6-96e8-534d-ba5f-d3eab68eb3db","slug":"electron-transfer-flavoprotein","display_name":"Human electron transfer flavoprotein / ETF","entity_type_key":"protein_complex"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_spans","value_text":"[{\"source_bundle\": \"artifacts/riboflavin_metabolism_sources.json\", \"source_key\": \"PMID15159392\", \"locator\": \"metadata.abstractText\", \"paragraph_index\": 0, \"char_start\": 0, \"char_end\": 1430, \"evidence_access\": \"primary-abstract\"}]","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human ETF-MCAD complex crystallography and solution interfacial mutagenesis.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"No nutrient intervention; structural or biochemical characterization.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Primary abstract supports mechanism; no inference about clinical MCAD supplementation response.","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":"Fatty-acid oxidation hands electrons from MCAD to a distinct ETF carrier.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[toogood-2004-etf-mcad] Extensive domain motion and electron transfer in the human electron transferring flavoprotein.medium chain Acyl-CoA dehydrogenase complex (2004). https://pubmed.ncbi.nlm.nih.gov/15159392/ DOI: 10.1074/jbc.m404884200","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Recombinant human protein complex","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"2193e1f8-adc1-5e9f-9915-7b010993188e","evidence_kind":"source_excerpt","locator":"Lines 741-752","start_line":741,"end_line":752,"excerpt":"### b2-met-mcad-etf-electron-transfer\nHuman MCAD and ETF form an electron-transfer complex in which a recognition loop anchors binding while the ETF FAD domain samples electron-transfer-compatible conformations.\nCondition category: normal\nnutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Fatty-acid oxidation hands electrons from MCAD to a distinct ETF carrier.\norganism: Homo sapiens\ntissue_or_cell_type: Recombinant human protein complex\nexperimental_model: Human ETF-MCAD complex crystallography and solution interfacial mutagenesis.\nlimitations: Primary abstract supports mechanism; no inference about clinical MCAD supplementation response.\nexposure: No nutrient intervention; structural or biochemical characterization.\nevidence_spans: [{\"source_bundle\": \"artifacts/riboflavin_metabolism_sources.json\", \"source_key\": \"PMID15159392\", \"locator\": \"metadata.abstractText\", \"paragraph_index\": 0, \"char_start\": 0, \"char_end\": 1430, \"evidence_access\": \"primary-abstract\"}]\n[toogood-2004-etf-mcad] Extensive domain motion and electron transfer in the human electron transferring flavoprotein.medium chain Acyl-CoA dehydrogenase complex (2004). https://pubmed.ncbi.nlm.nih.gov/15159392/ DOI: 10.1074/jbc.m404884200","model_system":"Human ETF-MCAD complex crystallography and solution interfacial mutagenesis.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [toogood-2004-etf-mcad] Extensive domain motion and electron transfer in the human electron transferring flavoprotein.medium chain Acyl-CoA dehydrogenase complex (2004). https://pubmed.ncbi.nlm.nih.gov/15159392/ DOI: 10.1074/jbc.m404884200","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}