{"id":"6e016211-2cc9-53fb-a903-65f27af76b2a","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:va-bco1-central-cleavage","predicate":"converts","statement":"Purified human BCO1 cleaved all-trans-beta-carotene centrally to all-trans-retinal.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"fcffc625-32db-5ba7-bb90-f577a1b07e43","mechanism_event_label":"BCO1 turns a carotenoid precursor into retinal.","subject":{"id":"d908f2a5-bc6d-5c6f-a692-668c79fae71b","slug":"bco1","display_name":"Beta-carotene oxygenase 1 / BCO1","entity_type_key":"protein"},"object":{"id":"194eccf2-c7a5-52a6-a0c6-1c1f6d0f3a3e","slug":"all-trans-retinal","display_name":"All-trans-retinal","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"fcffc625-32db-5ba7-bb90-f577a1b07e43","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:va-bco1-central-cleavage-event","event_type":"biochemical_relationship","label":"BCO1 turns a carotenoid precursor into retinal.","description":"Purified human BCO1 cleaved all-trans-beta-carotene centrally to all-trans-retinal.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"73c24cd4-9ae8-5897-8359-fa4d9e8edecb","slug":"beta-carotene","display_name":"All-trans-beta-carotene","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"899c7ab0-6f81-5b38-a6bd-fbb33d66ac8d","slug":"oxygen","display_name":"Molecular oxygen","entity_type_key":"small_molecule"},"role":"cosubstrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"d908f2a5-bc6d-5c6f-a692-668c79fae71b","slug":"bco1","display_name":"Beta-carotene oxygenase 1 / BCO1","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"194eccf2-c7a5-52a6-a0c6-1c1f6d0f3a3e","slug":"all-trans-retinal","display_name":"All-trans-retinal","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_location","value_text":"Figure 3","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified human BCO1 expressed in E. coli; substrate incubations and HPLC.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"20 micromolar beta-carotene, 500 ng enzyme/200 microliters, 37 C, 15 minutes.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Purified-enzyme rates do not determine dietary conversion efficiency.","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":"Homo sapiens protein expressed in Escherichia coli","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"outcome","value_text":"Purified human BCO1 cleaved all-trans-beta-carotene centrally to all-trans-retinal.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"BCO1 turns a carotenoid precursor into retinal.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[va-delasena-2013] Substrate specificity of purified recombinant human beta-carotene 15,15'-oxygenase (BCO1) (2013). https://pubmed.ncbi.nlm.nih.gov/24187135/ DOI: 10.1074/jbc.M113.507160","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cell-free enzyme","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"49f8eecc-c52f-5c3d-a43d-e8289992d840","evidence_kind":"source_excerpt","locator":"Lines 131-143","start_line":131,"end_line":143,"excerpt":"### va-bco1-central-cleavage\nPurified human BCO1 cleaved all-trans-beta-carotene centrally to all-trans-retinal.\nCondition category: normal\nnutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: BCO1 turns a carotenoid precursor into retinal.\norganism: Homo sapiens protein expressed in Escherichia coli\ntissue_or_cell_type: Cell-free enzyme\nexperimental_model: Purified human BCO1 expressed in E. coli; substrate incubations and HPLC.\nlimitations: Purified-enzyme rates do not determine dietary conversion efficiency.\nexposure: 20 micromolar beta-carotene, 500 ng enzyme/200 microliters, 37 C, 15 minutes.\noutcome: Purified human BCO1 cleaved all-trans-beta-carotene centrally to all-trans-retinal.\nevidence_location: Figure 3\n[va-delasena-2013] Substrate specificity of purified recombinant human beta-carotene 15,15'-oxygenase (BCO1) (2013). https://pubmed.ncbi.nlm.nih.gov/24187135/ DOI: 10.1074/jbc.M113.507160","model_system":"Purified human BCO1 expressed in E. coli; substrate incubations and HPLC.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [va-delasena-2013] Substrate specificity of purified recombinant human beta-carotene 15,15'-oxygenase (BCO1) (2013). https://pubmed.ncbi.nlm.nih.gov/24187135/ DOI: 10.1074/jbc.M113.507160","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}