{"id":"87723261-ea3a-5ab9-baa1-e5c6e4506c62","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:a-vision-rpe65-zinc-not-substitute","predicate":"does-not-restore","statement":"ZnCl2 did not restore isomerohydrolase activity after metal chelation in the bovine RPE assay, whereas FeSO4 did.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"8bbb71d4-0654-5ad7-bfc8-ef96fbfaee66","mechanism_event_label":"Zinc could not replace iron in this enzyme assay.","subject":{"id":"49c806c2-7041-5020-8b3b-fa04ffa122ac","slug":"zinc-ion","display_name":"Zinc(II) ion","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":"8bbb71d4-0654-5ad7-bfc8-ef96fbfaee66","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:a-vision-rpe65-zinc-not-substitute-event","event_type":"biochemical_relationship","label":"Zinc could not replace iron in this enzyme assay.","description":"ZnCl2 did not restore isomerohydrolase activity after metal chelation in the bovine RPE assay, whereas FeSO4 did.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"role":"successful rescue ion","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"49c806c2-7041-5020-8b3b-fa04ffa122ac","slug":"zinc-ion","display_name":"Zinc(II) ion","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 and zinc are not interchangeable RPE65 cofactors in the tested preparation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Metal-rescue comparison","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Does not test systemic zinc status or other zinc-dependent visual functions.","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","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Zinc could not replace iron in this enzyme assay.","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","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"9b44ee0c-5cef-546d-ac23-20d081e39d62","evidence_kind":"source_excerpt","locator":"Lines 689-699","start_line":689,"end_line":699,"excerpt":"### a-vision-rpe65-zinc-not-substitute\nZnCl2 did not restore isomerohydrolase activity after metal chelation in the bovine RPE assay, whereas FeSO4 did.\nCondition category: normal\nnutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Zinc could not replace iron in this enzyme assay.\norganism: Bos taurus\ntissue_or_cell_type: RPE microsomes\nexperimental_model: Metal-rescue comparison\nlimitations: Does not test systemic zinc status or other zinc-dependent visual functions.\ncross_nutrient: Iron and zinc are not interchangeable RPE65 cofactors in the tested preparation.\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":"Metal-rescue comparison","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}