{"id":"438eff67-c21d-5424-9139-187d050a13d7","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-gsr-gssg-to-gsh","predicate":"reduces","statement":"GSR reduces one glutathione-disulfide molecule to two reduced glutathione molecules using the NADPH/FAD catalytic relay.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"6943c2c4-0a20-593a-aa9a-7de70b2f7756","mechanism_event_label":"This enzyme recycles glutathione after oxidation.","subject":{"id":"ae04c12f-c0ac-5c8d-9ee2-76e58156d105","slug":"gsr","display_name":"Glutathione reductase / GSR","entity_type_key":"protein"},"object":{"id":"1d9b9d7b-3fdf-57af-b9dd-00194fa1de9e","slug":"oxidized-glutathione","display_name":"GSSG","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"6943c2c4-0a20-593a-aa9a-7de70b2f7756","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:b2-gsr-gssg-to-gsh-event","event_type":"biochemical_relationship","label":"This enzyme recycles glutathione after oxidation.","description":"GSR reduces one glutathione-disulfide molecule to two reduced glutathione molecules using the NADPH/FAD catalytic relay.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"1d9b9d7b-3fdf-57af-b9dd-00194fa1de9e","slug":"oxidized-glutathione","display_name":"GSSG","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"b44c9e27-4bbb-52d3-a022-14cddded5073","slug":"glutathione","display_name":"GSH","entity_type_key":"small_molecule"},"role":"product; two equivalents","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"4aba2a5e-8d06-5304-bb01-c0402b225a94","slug":"nadph","display_name":"NADPH","entity_type_key":"small_molecule"},"role":"electron donor","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"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":3,"notes":""},{"entity":{"id":"ae04c12f-c0ac-5c8d-9ee2-76e58156d105","slug":"gsr","display_name":"Glutathione reductase / GSR","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"B2-FAD supports GSH recycling; selenium-dependent GPX use of GSH is a separate reaction.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_location","value_text":"Results: NADPH binding; Fig 1 consensus cycle; GSH/GSSG complexes","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified human glutathione reductase crystals with natural substrates, 0.95-1.1-A resolution, chemically reduced controls.","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":"GSR is not glutathione peroxidase; this record does not show that B2 improves selenium repletion.","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":"This enzyme recycles glutathione after oxidation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[berkholz2008] Catalytic cycle of human glutathione reductase near 1 A resolution. (2008). https://pubmed.ncbi.nlm.nih.gov/18638483/ DOI: 10.1016/j.jmb.2008.06.083","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified human GSR","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"e699144e-21b7-573e-ab20-45078b6731a6","evidence_kind":"source_excerpt","locator":"Lines 1332-1344","start_line":1332,"end_line":1344,"excerpt":"### b2-gsr-gssg-to-gsh\nGSR reduces one glutathione-disulfide molecule to two reduced glutathione molecules using the NADPH/FAD catalytic relay.\nCondition category: normal\nnutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: This enzyme recycles glutathione after oxidation.\norganism: Homo sapiens\ntissue_or_cell_type: Purified human GSR\nexperimental_model: Purified human glutathione reductase crystals with natural substrates, 0.95-1.1-A resolution, chemically reduced controls.\nlimitations: GSR is not glutathione peroxidase; this record does not show that B2 improves selenium repletion.\nexposure: Purified-enzyme assay\ncross_nutrient: B2-FAD supports GSH recycling; selenium-dependent GPX use of GSH is a separate reaction.\nevidence_location: Results: NADPH binding; Fig 1 consensus cycle; GSH/GSSG complexes\n[berkholz2008] Catalytic cycle of human glutathione reductase near 1 A resolution. (2008). https://pubmed.ncbi.nlm.nih.gov/18638483/ DOI: 10.1016/j.jmb.2008.06.083","model_system":"Purified human glutathione reductase crystals with natural substrates, 0.95-1.1-A resolution, chemically reduced controls.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [berkholz2008] Catalytic cycle of human glutathione reductase near 1 A resolution. (2008). https://pubmed.ncbi.nlm.nih.gov/18638483/ DOI: 10.1016/j.jmb.2008.06.083","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. 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