{"id":"c428a41a-2ecc-5560-bc03-06b967736894","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-g6pd-fad-assay-limit","predicate":"deficiency_changes_interpretation_of_fad_stimulation","statement":"In G6PD-deficient erythrocytes, glutathione reductase was usually already FAD-saturated despite evidence of low FMN-dependent oxidase activity.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"7663194a-60a8-5a43-b109-334af33aa613","mechanism_event_label":"A red-cell FAD saturation test can look adequate while another B2-dependent enzyme system is poorly supplied.","subject":{"id":"f65184d1-6b79-5e38-8137-a06a40e94e36","slug":"g6pd","display_name":"Glucose-6-phosphate dehydrogenase / G6PD","entity_type_key":"protein"},"object":{"id":"34eee5dc-1157-5374-8f5c-ce7ec87156a4","slug":"erythrocyte-glutathione-reductase-activation-coefficient","display_name":"Erythrocyte glutathione reductase activation coefficient / EGRAC","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"7663194a-60a8-5a43-b109-334af33aa613","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-g6pd-fad-assay-limit-event","event_type":"observed_intervention","label":"A red-cell FAD saturation test can look adequate while another B2-dependent enzyme system is poorly supplied.","description":"In G6PD-deficient erythrocytes, glutathione reductase was usually already FAD-saturated despite evidence of low FMN-dependent oxidase activity.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"ae04c12f-c0ac-5c8d-9ee2-76e58156d105","slug":"gsr","display_name":"Glutathione reductase / GSR","entity_type_key":"protein"},"role":"assayed_enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"e2cd7179-f218-54e8-9ce9-7a836ae35fac","slug":"fad","display_name":"FAD","entity_type_key":"small_molecule"},"role":"bound_cofactor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"d3eacf85-1a35-546d-bd30-161474dd9691","slug":"fmn","display_name":"Flavin mononucleotide","entity_type_key":"small_molecule"},"role":"other_cofactor","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"a01d08b9-a749-5bc3-934b-af0b35024b54","slug":"pnpo","display_name":"Pyridoxine 5-prime-phosphate oxidase / PNPO","entity_type_key":"protein"},"role":"other_assayed_enzyme","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"f65184d1-6b79-5e38-8137-a06a40e94e36","slug":"g6pd","display_name":"Glucose-6-phosphate dehydrogenase / G6PD","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"34eee5dc-1157-5374-8f5c-ce7ec87156a4","slug":"erythrocyte-glutathione-reductase-activation-coefficient","display_name":"Erythrocyte glutathione reductase activation coefficient / EGRAC","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"cross_nutrient","value_text":"G6PD genotype and distinct flavin pools alter interpretation of B2/B6-linked assays.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human erythrocytes from G6PD deficiency, heterozygous beta-thalassemia and controls.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"In-vitro FAD stimulation of glutathione reductase and PNP oxidase activity, with oral-riboflavin response observations.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Human red-cell observation; the proposed faster FMN-to-FAD flux was an interpretation, not a directly measured universal mechanism.","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":"A red-cell FAD saturation test can look adequate while another B2-dependent enzyme system is poorly supplied.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b2-anderson1987] Glutathione reductase activity and its relationship to pyridoxine phosphate activity in G6PD deficiency (1987). https://pubmed.ncbi.nlm.nih.gov/3582603/ DOI: 10.1111/j.1600-0609.1987.tb01417.x","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human clinical setting","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"15246945-400e-5024-90b3-8f2d057e2840","evidence_kind":"source_excerpt","locator":"Lines 1666-1677","start_line":1666,"end_line":1677,"excerpt":"### b2-g6pd-fad-assay-limit\nIn G6PD-deficient erythrocytes, glutathione reductase was usually already FAD-saturated despite evidence of low FMN-dependent oxidase activity.\nCondition category: biomarker_context\nnutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A red-cell FAD saturation test can look adequate while another B2-dependent enzyme system is poorly supplied.\norganism: Homo sapiens\ntissue_or_cell_type: Human clinical setting\nexperimental_model: Human erythrocytes from G6PD deficiency, heterozygous beta-thalassemia and controls.\nlimitations: Human red-cell observation; the proposed faster FMN-to-FAD flux was an interpretation, not a directly measured universal mechanism.\nexposure: In-vitro FAD stimulation of glutathione reductase and PNP oxidase activity, with oral-riboflavin response observations.\ncross_nutrient: G6PD genotype and distinct flavin pools alter interpretation of B2/B6-linked assays.\n[b2-anderson1987] Glutathione reductase activity and its relationship to pyridoxine phosphate activity in G6PD deficiency (1987). https://pubmed.ncbi.nlm.nih.gov/3582603/ DOI: 10.1111/j.1600-0609.1987.tb01417.x","model_system":"Human erythrocytes from G6PD deficiency, heterozygous beta-thalassemia and controls.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b2-anderson1987] Glutathione reductase activity and its relationship to pyridoxine phosphate activity in G6PD deficiency (1987). https://pubmed.ncbi.nlm.nih.gov/3582603/ DOI: 10.1111/j.1600-0609.1987.tb01417.x","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}