{"id":"5441378f-817b-5e98-b7fa-de4a451684f6","stable_key":"aad5a443-96e9-52eb-963a-812e90f9f896:lycopene-bco1-ring-rule","predicate":"was_reported_to_require_ring_for","statement":"The 2002 human BCO1 study concluded that efficient cleavage required at least one unsubstituted beta-ionone ring.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"f26d1dee-a6cd-5fb3-b2a8-1d769e895096","mechanism_event_label":"An earlier experiment proposed a substrate rule that the later lycopene result challenges.","subject":{"id":"d908f2a5-bc6d-5c6f-a692-668c79fae71b","slug":"bco1","display_name":"Beta-carotene oxygenase 1 / BCO1","entity_type_key":"protein"},"object":{"id":"dddeed2f-7aa1-5c3f-9a47-c7cc8d6ad382","slug":"human-bco1-substrate-specificity","display_name":"Human BCO1 carotenoid substrate specificity","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"f26d1dee-a6cd-5fb3-b2a8-1d769e895096","stable_key":"aad5a443-96e9-52eb-963a-812e90f9f896:lycopene-bco1-ring-rule-event","event_type":"biochemical_relationship","label":"An earlier experiment proposed a substrate rule that the later lycopene result challenges.","description":"The 2002 human BCO1 study concluded that efficient cleavage required at least one unsubstituted beta-ionone ring.","status":"provisional","compartment":null,"participants":[{"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":0,"notes":""},{"entity":{"id":"dddeed2f-7aa1-5c3f-9a47-c7cc8d6ad382","slug":"human-bco1-substrate-specificity","display_name":"Human BCO1 carotenoid substrate specificity","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/lycopene-research/11960992.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"42dd2ebd13adbf84c3f6f89de7374995253ff8f433cc72f32191eceb3c7eb3a0\", \"start_char\": 0, \"end_char\": 1324, \"text_sha256\": \"42dd2ebd13adbf84c3f6f89de7374995253ff8f433cc72f32191eceb3c7eb3a0\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified recombinant human enzyme substrate-specificity analysis","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Carotenoid substrate panel","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Abstract supports the reported ring requirement; it does not supply a lycopene-specific numerical detection limit.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Lycopene research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"lycopene","display_name":"Lycopene","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Human BCO1 expressed in insect cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"An earlier experiment proposed a substrate rule that the later lycopene result challenges.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[lycopene-p11960992] Biochemical properties of purified recombinant human beta-carotene 15,15'-monooxygenase. (2002). https://pubmed.ncbi.nlm.nih.gov/11960992/ DOI: 10.1074/jbc.m202756200","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cell-free enzyme assay","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c0bb3e50-7d39-5541-9e88-85c61927470f","evidence_kind":"source_excerpt","locator":"Lines 390-401","start_line":390,"end_line":401,"excerpt":"### lycopene-bco1-ring-rule\nThe 2002 human BCO1 study concluded that efficient cleavage required at least one unsubstituted beta-ionone ring.\nCondition category: normal\nnutrient_topic: Lycopene research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: An earlier experiment proposed a substrate rule that the later lycopene result challenges.\norganism: Human BCO1 expressed in insect cells\ntissue_or_cell_type: Cell-free enzyme assay\nexperimental_model: Purified recombinant human enzyme substrate-specificity analysis\nlimitations: Abstract supports the reported ring requirement; it does not supply a lycopene-specific numerical detection limit.\nexposure: Carotenoid substrate panel\nevidence_span: {\"source_cache\": \"artifacts/lycopene-research/11960992.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"42dd2ebd13adbf84c3f6f89de7374995253ff8f433cc72f32191eceb3c7eb3a0\", \"start_char\": 0, \"end_char\": 1324, \"text_sha256\": \"42dd2ebd13adbf84c3f6f89de7374995253ff8f433cc72f32191eceb3c7eb3a0\"}\n[lycopene-p11960992] Biochemical properties of purified recombinant human beta-carotene 15,15'-monooxygenase. (2002). https://pubmed.ncbi.nlm.nih.gov/11960992/ DOI: 10.1074/jbc.m202756200","model_system":"Purified recombinant human enzyme substrate-specificity analysis","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [lycopene-p11960992] Biochemical properties of purified recombinant human beta-carotene 15,15'-monooxygenase. (2002). https://pubmed.ncbi.nlm.nih.gov/11960992/ DOI: 10.1074/jbc.m202756200","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"d1e09874-8bde-548f-9664-26ad5eedb3c7","stable_key":"import-aad5a443-96e9-52eb-963a-812e90f9f896","title":"Lycopene: absorption, metabolism, nutrient connections and human outcomes (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":"9a53dd877de8b71d446f741026477c0fd70a38edac89f6f25339a371a627a59a","revision_id":"2e68d88d-a689-5959-9f9c-1552dd089c22","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[{"id":"cdb71a89-55df-5274-94a8-ef5efcac0e2d","title":"Human BCO1: does efficient cleavage require a beta-ionone ring?","kind":"qualification","status":"open","why":"The 2002 purified human-enzyme study inferred a ring requirement; the 2013 study measured cleavage of acyclic lycopene to acycloretinal. These are competing published substrate-specificity conclusions, not an error in our draft. Expression system, purification, substrate dispersion and oxidation controls are candidate explanations; this collection does not establish which explains the discrepancy.","resolution":"Retain both experimental conclusions with their assay context. Treat the 2013 reaction as demonstrated under its conditions, without assuming dominant human in-vivo flux. Neither interpretation makes lycopene a provitamin A source.","created_at":"2026-09-17 23:25:00","record_type":"conflict","display_label":"Recorded conflict","record_url":"/conflicts/cdb71a89-55df-5274-94a8-ef5efcac0e2d","sides":[{"conflict_id":"cdb71a89-55df-5274-94a8-ef5efcac0e2d","ordinal":0,"label":"An earlier experiment proposed a substrate rule that the later lycopene result challenges.","revision_id":"2e68d88d-a689-5959-9f9c-1552dd089c22","start_line":390,"end_line":401,"quote":"### lycopene-bco1-ring-rule\nThe 2002 human BCO1 study concluded that efficient cleavage required at least one unsubstituted beta-ionone ring.\nCondition category: normal\nnutrient_topic: Lycopene research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: An earlier experiment proposed a substrate rule that the later lycopene result challenges.\norganism: Human BCO1 expressed in insect cells\ntissue_or_cell_type: Cell-free enzyme assay\nexperimental_model: Purified recombinant human enzyme substrate-specificity analysis\nlimitations: Abstract supports the reported ring requirement; it does not supply a lycopene-specific numerical detection limit.\nexposure: Carotenoid substrate panel\nevidence_span: {\"source_cache\": \"artifacts/lycopene-research/11960992.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"42dd2ebd13adbf84c3f6f89de7374995253ff8f433cc72f32191eceb3c7eb3a0\", \"start_char\": 0, \"end_char\": 1324, \"text_sha256\": \"42dd2ebd13adbf84c3f6f89de7374995253ff8f433cc72f32191eceb3c7eb3a0\"}\n[lycopene-p11960992] Biochemical properties of purified recombinant human beta-carotene 15,15'-monooxygenase. (2002). https://pubmed.ncbi.nlm.nih.gov/11960992/ DOI: 10.1074/jbc.m202756200","source_key":"import-aad5a443-96e9-52eb-963a-812e90f9f896","source_title":"Lycopene: absorption, metabolism, nutrient connections and human outcomes (2026-09-17)","claim_ids":["5441378f-817b-5e98-b7fa-de4a451684f6"]},{"conflict_id":"cdb71a89-55df-5274-94a8-ef5efcac0e2d","ordinal":1,"label":"This product lacks the ring of vitamin-A retinal; cleavage does not make lycopene a vitamin A source.","revision_id":"2e68d88d-a689-5959-9f9c-1552dd089c22","start_line":377,"end_line":388,"quote":"### lycopene-bco1-acycloretinal\nPurified recombinant human BCO1 generated acycloretinal from lycopene, with reported catalytic efficiency similar to beta-carotene.\nCondition category: normal\nnutrient_topic: Lycopene research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: This product lacks the ring of vitamin-A retinal; cleavage does not make lycopene a vitamin A source.\norganism: Human BCO1 expressed in E. coli\ntissue_or_cell_type: Cell-free carotenoid cleavage\nexperimental_model: Purified recombinant human enzyme kinetics\nlimitations: Activity in a purified enzyme system does not establish dominant in-vivo flux; acycloretinal is not retinal or vitamin A.\nexposure: Substrate panel; product chromatography\nevidence_span: {\"source_cache\": \"artifacts/lycopene-research/24187135.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"cf8ce69a4772c58e274590a2e3f251bed46de77b4d844b54c98d39fcd27e3e91\", \"start_char\": 0, \"end_char\": 1772, \"text_sha256\": \"cf8ce69a4772c58e274590a2e3f251bed46de77b4d844b54c98d39fcd27e3e91\"}\n[lycopene-p24187135] Substrate specificity of purified recombinant human β-carotene 15,15'-oxygenase (BCO1). (2013). https://pubmed.ncbi.nlm.nih.gov/24187135/ DOI: 10.1074/jbc.m113.507160","source_key":"import-aad5a443-96e9-52eb-963a-812e90f9f896","source_title":"Lycopene: absorption, metabolism, nutrient connections and human outcomes (2026-09-17)","claim_ids":["227fc554-1eec-52df-99bb-aaaeda2cf344"]}]}],"corrections":[],"research":null}