{"id":"86edbd91-9c4d-5d6f-bb25-0cadd33b51b8","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:a-vision-rpe65-iron","predicate":"enables","statement":"FeSO4 restored chelator-inhibited RPE65 isomerohydrolase activity in bovine microsomes and recombinant assays; ferric salts did not.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"f1ea0a77-80d4-5270-a170-8465bf34a681","mechanism_event_label":"Ferrous iron is required for this vitamin A recycling enzyme.","subject":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"object":{"id":"4b5339c8-6f83-5d4c-a3b4-79c3c440c23d","slug":"rpe65","display_name":"RPE65 retinoid isomerohydrolase","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"f1ea0a77-80d4-5270-a170-8465bf34a681","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:a-vision-rpe65-iron-event","event_type":"biochemical_relationship","label":"Ferrous iron is required for this vitamin A recycling enzyme.","description":"FeSO4 restored chelator-inhibited RPE65 isomerohydrolase activity in bovine microsomes and recombinant assays; ferric salts did not.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"4a978267-139b-518d-bdc6-e16cda6f5225","slug":"11-cis-retinol","display_name":"11-cis-retinol","entity_type_key":"small_molecule"},"role":"measured product","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"4b5339c8-6f83-5d4c-a3b4-79c3c440c23d","slug":"rpe65","display_name":"RPE65 retinoid isomerohydrolase","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Iron availability at RPE65 enables formation of the cis-retinoid visual-cycle intermediate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Chelation and metal rescue","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This is enzyme-cofactor evidence, not a human iron-deficiency threshold.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin A research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-a","display_name":"Vitamin A","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Bos taurus; recombinant RPE65 in human 293A cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Ferrous iron is required for this vitamin A recycling enzyme.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[moiseyev-2006] RPE65 is an iron(II)-dependent isomerohydrolase in the retinoid visual cycle (2006). https://pubmed.ncbi.nlm.nih.gov/16319067/ DOI: 10.1074/jbc.M508903200","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"RPE microsomes and cultured-cell preparations","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"4385880c-f756-5d1e-93b6-7e2bdda6868c","evidence_kind":"source_excerpt","locator":"Lines 677-687","start_line":677,"end_line":687,"excerpt":"### a-vision-rpe65-iron\nFeSO4 restored chelator-inhibited RPE65 isomerohydrolase activity in bovine microsomes and recombinant assays; ferric salts did not.\nCondition category: normal\nnutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Ferrous iron is required for this vitamin A recycling enzyme.\norganism: Bos taurus; recombinant RPE65 in human 293A cells\ntissue_or_cell_type: RPE microsomes and cultured-cell preparations\nexperimental_model: Chelation and metal rescue\nlimitations: This is enzyme-cofactor evidence, not a human iron-deficiency threshold.\ncross_nutrient: Iron availability at RPE65 enables formation of the cis-retinoid visual-cycle intermediate.\n[moiseyev-2006] RPE65 is an iron(II)-dependent isomerohydrolase in the retinoid visual cycle (2006). https://pubmed.ncbi.nlm.nih.gov/16319067/ DOI: 10.1074/jbc.M508903200","model_system":"Chelation and metal rescue","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [moiseyev-2006] RPE65 is an iron(II)-dependent isomerohydrolase in the retinoid visual cycle (2006). https://pubmed.ncbi.nlm.nih.gov/16319067/ DOI: 10.1074/jbc.M508903200","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"0c5474e2-be48-547b-b287-9c07a59c9ff1","stable_key":"import-dff9f743-3766-5f20-a71e-d6d2bd5bfb6f","title":"Vitamin A: forms, mechanisms, deficiency and excess (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":"b217224b262abbd77d6a0c8c9beefff9c022fae4d31e2a5273915d769b9a6546","revision_id":"61008909-871f-575c-b5e2-21542689ea3c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}