{"id":"605b72ca-00db-500b-b9b2-c557a2681417","stable_key":"research:gpx3-reduces-extracellular-peroxide","predicate":"reduces","statement":"Purified human plasma glutathione peroxidase reduced hydrogen peroxide using glutathione.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"literature_reviewed:direct_experimental","direction":"negative","is_public":true,"mechanism_event_id":"427228ff-b116-5d4f-bb6d-21cf122e604b","mechanism_event_label":"GPX3 can remove peroxide outside cells.","subject":{"id":"32f7aa34-135f-5bfb-9189-81634ad4a824","slug":"gpx3","display_name":"GPX3","entity_type_key":"protein"},"object":{"id":"da9d64bc-69d4-5d97-90a4-8f0ed03e0ac8","slug":"hydrogen-peroxide","display_name":"Hydrogen peroxide","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"427228ff-b116-5d4f-bb6d-21cf122e604b","stable_key":"research:gpx3-reduces-extracellular-peroxide","event_type":"peroxide-reduction","label":"GPX3 can remove peroxide outside cells.","description":"Purified human plasma glutathione peroxidase reduced hydrogen peroxide using glutathione.","status":"active","compartment":{"slug":"extracellular-space","display_name":"Extracellular space"},"participants":[{"entity":{"id":"32f7aa34-135f-5bfb-9189-81634ad4a824","slug":"gpx3","display_name":"GPX3","entity_type_key":"protein"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"da9d64bc-69d4-5d97-90a4-8f0ed03e0ac8","slug":"hydrogen-peroxide","display_name":"Hydrogen peroxide","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"b44c9e27-4bbb-52d3-a022-14cddded5073","slug":"glutathione","display_name":"GSH","entity_type_key":"small_molecule"},"role":"reducing-cosubstrate","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"1d9b9d7b-3fdf-57af-b9dd-00194fa1de9e","slug":"oxidized-glutathione","display_name":"GSSG","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"d31225b7-8e94-5857-9ea1-67ac794b1f15","slug":"water","display_name":"H2O","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"cell_type","value_text":"plasma","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified enzyme kinetics","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Assay glutathione availability does not define every physiological electron donor.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"organism","value_text":"human","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"fe0bf34f-1167-5656-8dd2-3ebba5a1b28f","evidence_kind":"curated_literature_summary","locator":"lines 678-688","start_line":678,"end_line":688,"excerpt":"## gpx3-reduces-extracellular-peroxide\n\nGPX3 can remove peroxide outside cells.\n\nPurified human plasma glutathione peroxidase reduced hydrogen peroxide using glutathione.\n\nOrganism: human\nCell type: plasma\nExperimental model: Purified enzyme kinetics\nLimitations: Assay glutathione availability does not define every physiological electron donor.\nPrimary reference: [Characterization of the major hydroperoxide-reducing activity of human plasma. Purification and properties of a selenium-dependent glutathione peroxidase.](https://www.sciencedirect.com/science/article/pii/S0021925818453926)","model_system":"Purified enzyme kinetics","directness":"author_interpretation","verification_status":"secondary_verified","notes":"Curated summary; inspect the linked primary papers for original methods and results.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"4f892f13-06ea-5199-a33c-a703f35c80ae","stable_key":"selenium-research-2026-09-17","title":"Selenium: literature corrections and mechanism additions","document_type":"curated_literature_review","citation_label":"Metabolic Ledger literature curation, 17 September 2026; primary papers linked individually","file_path":"","sha256":"0b818b10c1c7120e5caf7f4d4019d7bd025d745692e424f515d3ef903c9ab7f3","revision_id":"80984e03-5f0f-5877-8094-afef7637444e","review_status":"secondary_verified","notes":"Secondary curated summaries of primary experiments, with explicit models and limitations. Not archived primary full text."}}],"relations":[],"conflicts":[],"corrections":[],"research":{"topic":"extracellular-redox","plain_language":"GPX3 can remove peroxide outside cells.","evidence_scope":"direct_experimental","papers":[{"key":"maddipati-1987-plasma-gpx","title":"Characterization of the major hydroperoxide-reducing activity of human plasma. Purification and properties of a selenium-dependent glutathione peroxidase.","url":"https://www.sciencedirect.com/science/article/pii/S0021925818453926","doi":"10.1016/S0021-9258(18)45392-6","year":1987,"model":"Purified human plasma glutathione peroxidase","summary":"Measures selenium-containing plasma peroxidase catalysis with glutathione and peroxide substrates."}]}}