{"id":"4e50653f-71ed-5981-ac8e-728cc10d54c0","stable_key":"3c852f36-7951-5fd9-9013-d771a8d16d8a:vae-des1-retinol-isomerization","predicate":"catalyzes_in_assay","statement":"Homogenates of DES1-expressing HEK293T cells formed 11-cis-retinol from all-trans-retinol, alongside more abundant alternative cis isomers.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"3f16a5d1-bfa4-5496-b2ac-e45234f08871","mechanism_event_label":"DES1-associated activity made some 11-cis-retinol in biochemical assays.","subject":{"id":"743b0a10-1977-5b02-a116-1c53c6700b3d","slug":"degs1","display_name":"Dihydroceramide desaturase 1 / DES1","entity_type_key":"protein"},"object":{"id":"4a978267-139b-518d-bdc6-e16cda6f5225","slug":"11-cis-retinol","display_name":"11-cis-retinol","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"3f16a5d1-bfa4-5496-b2ac-e45234f08871","stable_key":"3c852f36-7951-5fd9-9013-d771a8d16d8a:vae-des1-retinol-isomerization-event","event_type":"biochemical_relationship","label":"DES1-associated activity made some 11-cis-retinol in biochemical assays.","description":"Homogenates of DES1-expressing HEK293T cells formed 11-cis-retinol from all-trans-retinol, alongside more abundant alternative cis isomers.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"743b0a10-1977-5b02-a116-1c53c6700b3d","slug":"degs1","display_name":"Dihydroceramide desaturase 1 / DES1","entity_type_key":"protein"},"role":"expressed candidate isomerase","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"148c57d8-c658-5769-89e8-1194cef2a782","slug":"retinol","display_name":"All-trans-retinol","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"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":2,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"false","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_location","value_text":"Figure 3a-d; Results: DES1 catalyzes equilibrium isomerization","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human DES1 expression; HPLC isomer analysis","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Retinol isomerase assays in darkness at 37 degrees Celsius.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Activity in homogenates does not establish its quantitative contribution or necessity in an intact visual cycle.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient","value_text":"Vitamin A","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-a","display_name":"Vitamin A","entity_type_key":"chemical_species"}},{"dimension":"nutrient_topic","value_text":"Vitamin A expansion 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":"Homo sapiens protein/cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"DES1-associated activity made some 11-cis-retinol in biochemical assays.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[vav-kaylor2013] Identification of DES1 as a vitamin A isomerase in Müller glial cells of the retina. (2013). https://pubmed.ncbi.nlm.nih.gov/23143414/ DOI: 10.1038/nchembio.1114","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"HEK293T homogenates","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"87cce1c9-4b0d-5a35-97e4-aa8ee19dc97f","evidence_kind":"source_excerpt","locator":"Lines 558-571","start_line":558,"end_line":571,"excerpt":"### vae-des1-retinol-isomerization\nHomogenates of DES1-expressing HEK293T cells formed 11-cis-retinol from all-trans-retinol, alongside more abundant alternative cis isomers.\nCondition category: normal\nnutrient_topic: Vitamin A expansion research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: DES1-associated activity made some 11-cis-retinol in biochemical assays.\norganism: Homo sapiens protein/cells\ntissue_or_cell_type: HEK293T homogenates\nexperimental_model: Recombinant human DES1 expression; HPLC isomer analysis\nlimitations: Activity in homogenates does not establish its quantitative contribution or necessity in an intact visual cycle.\nexposure: Retinol isomerase assays in darkness at 37 degrees Celsius.\ncross_nutrient: false\nevidence_location: Figure 3a-d; Results: DES1 catalyzes equilibrium isomerization\nnutrient: Vitamin A\n[vav-kaylor2013] Identification of DES1 as a vitamin A isomerase in Müller glial cells of the retina. (2013). https://pubmed.ncbi.nlm.nih.gov/23143414/ DOI: 10.1038/nchembio.1114","model_system":"Recombinant human DES1 expression; HPLC isomer analysis","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [vav-kaylor2013] Identification of DES1 as a vitamin A isomerase in Müller glial cells of the retina. (2013). https://pubmed.ncbi.nlm.nih.gov/23143414/ DOI: 10.1038/nchembio.1114","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"83131a07-353f-5301-9ce6-50754c194952","stable_key":"import-3c852f36-7951-5fd9-9013-d771a8d16d8a","title":"Vitamin A expansion: reproduction, light-driven vision and shared mechanisms (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. 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