{"id":"c39e7a2d-7710-56b0-9570-24a588378435","stable_key":"79018983-9179-5c1a-8e7a-d6f47a13582b:ki-lpo-heme","predicate":"cofactor_of","statement":"The LPO structure contains covalently attached heme; peroxide sits between its iron and distal His109.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"e28a7760-a6d0-5aa0-ab9e-297e5f416c0f","mechanism_event_label":"Iron-containing heme positions peroxide in the enzyme.","subject":{"id":"2e1f7e0a-8b54-5ea3-9d34-01e7167f9097","slug":"heme","display_name":"Heme","entity_type_key":"small_molecule"},"object":{"id":"3d671567-4fb6-5b5f-a328-156987d5b396","slug":"lactoperoxidase-family","display_name":"Lactoperoxidase enzyme family","entity_type_key":"protein_family"},"evidence_count":1,"mechanism_event":{"id":"e28a7760-a6d0-5aa0-ab9e-297e5f416c0f","stable_key":"79018983-9179-5c1a-8e7a-d6f47a13582b:ki-lpo-heme-event","event_type":"observed_relationship","label":"Iron-containing heme positions peroxide in the enzyme.","description":"The LPO structure contains covalently attached heme; peroxide sits between its iron and distal His109.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"2e1f7e0a-8b54-5ea3-9d34-01e7167f9097","slug":"heme","display_name":"Heme","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"3d671567-4fb6-5b5f-a328-156987d5b396","slug":"lactoperoxidase-family","display_name":"Lactoperoxidase enzyme family","entity_type_key":"protein_family"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"da9d64bc-69d4-5d97-90a4-8f0ed03e0ac8","slug":"hydrogen-peroxide","display_name":"Hydrogen peroxide","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"89bcaf42-b4ab-5760-8c2e-44eace10cee0","slug":"iron","display_name":"Iron","entity_type_key":"nutrient_element"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Purified LPO crystallography and activity assays; ammonium iodide supplied the anion, not KI.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure_category","value_text":"Study-specific exposure, including pharmacological and in-vitro conditions; normal is the schema fallback outside the three availability categories.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Structural/biochemical model; enzyme species not assigned from abstract. Cofactor chemistry does not establish dietary iron responsiveness.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Potassium iodide research collection; shared-anion and comparator studies are not all KI interventions.","comparator":null,"unit":null,"notes":"","entity":{"slug":"potassium-iodide","display_name":"Potassium iodide","entity_type_key":"chemical_species"}},{"dimension":"plain_language","value_text":"Iron-containing heme positions peroxide in the enzyme.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Structure of a ternary complex of lactoperoxidase with iodide and hydrogen peroxide at 1.77 Å resolution. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33882424/ · DOI 10.1016/j.jinorgbio.2021.111461","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"565c3614-f061-5475-b300-350dcbb0fb1c","evidence_kind":"source_excerpt","locator":"Lines 216-222","start_line":216,"end_line":222,"excerpt":"## ki-lpo-heme\nIron-containing heme positions peroxide in the enzyme.\nThe LPO structure contains covalently attached heme; peroxide sits between its iron and distal His109.\nModel: Purified LPO crystallography and activity assays; ammonium iodide supplied the anion, not KI.\nLimitations: Structural/biochemical model; enzyme species not assigned from abstract. Cofactor chemistry does not establish dietary iron responsiveness.\nEvidence location: Primary abstract\nStructure of a ternary complex of lactoperoxidase with iodide and hydrogen peroxide at 1.77 Å resolution. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33882424/ · DOI 10.1016/j.jinorgbio.2021.111461","model_system":"Purified LPO crystallography and activity assays; ammonium iodide supplied the anion, not KI.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Curation paraphrase; primary evidence location and source kind retained above.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"dc3ce411-f68f-5eb8-87c1-1592665f9cb6","stable_key":"import-79018983-9179-5c1a-8e7a-d6f47a13582b","title":"Potassium iodide: thyroid and non-thyroid mechanisms, interactions and discovery questions (2026-09-18)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary-study references, chemical references and label statements individually identified. Not publisher full text.","file_path":"","sha256":"3ff9da818dd7a763a59c6abcff2eaee136d7f887a777034feaa5ba304a8fa6ce","revision_id":"53f2ae88-8a91-5326-ac49-3bb510ca78c3","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}