{"id":"f29b6a58-c78c-5329-b44b-9263a2213f08","stable_key":"c836a883-ac18-5eb2-9971-2f0b542feba8:yeast-gssa-reduction","predicate":"reported_relationship","statement":"Purified yeast glutathione reductase used GSSA as a substrate with NADPH consumption; apparent Km was 0.50 mM.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"ea786e33-cdaf-562d-8828-59df92d48a74","mechanism_event_label":"Purified yeast glutathione reductase used GSSA as a substrate with NADPH consumption; apparent Km was 0.50 mM.","subject":{"id":"314bf91b-9d57-526d-9c1f-1987c8af718d","slug":"yeast-glr1","display_name":"Saccharomyces cerevisiae glutathione reductase / Glr1","entity_type_key":"protein"},"object":{"id":"9cc0e4f3-3eb8-5402-b131-f79f34a044fd","slug":"yeast-gssa-reductase-activity","display_name":"NADPH-dependent GSSA reduction by purified yeast glutathione reductase","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"ea786e33-cdaf-562d-8828-59df92d48a74","stable_key":"c836a883-ac18-5eb2-9971-2f0b542feba8:yeast-gssa-reduction-event","event_type":"biochemical_relationship","label":"Purified yeast glutathione reductase used GSSA as a substrate with NADPH consumption; apparent Km was 0.50 mM.","description":"**GSSA recycling and NADPH.** Purified yeast glutathione reductase reduced GSSA with NADPH consumption. Reported apparent Km values were 0.50 mM for GSSA and 0.07 mM for GSSG. They do not establish an eightfold difference in catalytic efficiency: turnover and assay differences matter, and the GSSA measurement deliberately omitted the DTNB cycling reagent used for GSSG. GSSA also supported growth of glutathione-synthesis-defective yeast. That rescue is consistent with recovery of usable glutathione, but it is not a human GSR experiment or proof that this enzyme was the exclusive route in living cells. [Horn 2018](https://pmc.ncbi.nlm.nih.gov/articles/PMC6070820/)","status":"provisional","compartment":null,"participants":[{"entity":{"id":"314bf91b-9d57-526d-9c1f-1987c8af718d","slug":"yeast-glr1","display_name":"Saccharomyces cerevisiae glutathione reductase / Glr1","entity_type_key":"protein"},"role":"tested factor","stoichiometry":null,"state_label":"as reported","sequence_order":0,"notes":""},{"entity":{"id":"9cc0e4f3-3eb8-5402-b131-f79f34a044fd","slug":"yeast-gssa-reductase-activity","display_name":"NADPH-dependent GSSA reduction by purified yeast glutathione reductase","entity_type_key":"cellular_process"},"role":"measured outcome","stoichiometry":null,"state_label":"not_reported","sequence_order":1,"notes":""},{"entity":{"id":"abc6eee3-1846-5180-9cc9-93379e6a02c9","slug":"s-allylmercaptoglutathione","display_name":"S-Allylmercaptoglutathione / GSSA","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":2,"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":3,"notes":""},{"entity":{"id":"b44c9e27-4bbb-52d3-a022-14cddded5073","slug":"glutathione","display_name":"GSH","entity_type_key":"small_molecule"},"role":"recovered reduced thiol","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full text available; selected claim-relevant methods, results, tables/figures and limitations reviewed. Supplemental proteome and all secondary findings are not exhaustively extracted.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified commercial Saccharomyces cerevisiae enzyme; NADPH absorbance assay without DTNB.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"interpretation_status","value_text":"Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Not human GSR validation. GSSG comparator used a different assay, and Km alone does not measure catalytic efficiency.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Purified yeast glutathione reductase used GSSA as a substrate with NADPH consumption; apparent Km was 0.50 mM.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"<i>S</i>-allylmercaptoglutathione Is a Substrate for Glutathione Reductase (E.C. 1.8.1.7) from Yeast (<i>Saccharomyces cerevisiae</i>). | 2018 | DOI 10.3390/antiox7070086 | PMID 29986384 | https://pubmed.ncbi.nlm.nih.gov/29986384/ | https://pmc.ncbi.nlm.nih.gov/articles/PMC6070820/ | https://doi.org/10.3390/antiox7070086","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"source_locator","value_text":"Reviewed reference lines 47-47; exact primary location described in quoted passage where extracted.","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c435399f-b18a-5099-b748-1c180595b5bd","evidence_kind":"source_excerpt","locator":"Lines 47-47","start_line":47,"end_line":47,"excerpt":"**GSSA recycling and NADPH.** Purified yeast glutathione reductase reduced GSSA with NADPH consumption. Reported apparent Km values were 0.50 mM for GSSA and 0.07 mM for GSSG. They do not establish an eightfold difference in catalytic efficiency: turnover and assay differences matter, and the GSSA measurement deliberately omitted the DTNB cycling reagent used for GSSG. GSSA also supported growth of glutathione-synthesis-defective yeast. That rescue is consistent with recovery of usable glutathione, but it is not a human GSR experiment or proof that this enzyme was the exclusive route in living cells. [Horn 2018](https://pmc.ncbi.nlm.nih.gov/articles/PMC6070820/)","model_system":"Purified commercial Saccharomyces cerevisiae enzyme; NADPH absorbance assay without DTNB.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Exact excerpt of the retained AI-assisted reviewed reference; primary sources are cited in primary_references and access scope is retained. Not a verbatim quotation from a primary paper.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"10820a6b-594a-547d-97f9-906ab4cc1d6e","stable_key":"import-c836a883-ac18-5eb2-9971-2f0b542feba8","title":"Allicin: detailed mechanisms of action (reviewed 5 October 2026)","document_type":"imported_text","citation_label":"Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication.","file_path":"","sha256":"2475d3eb681100a0a34577a47b7cba5b251df866fbd6ce795122ccabee360018","revision_id":"590df96d-2ed1-5763-b04c-bf0e096e603c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}