{"id":"87586ee8-4fc3-5ba7-9257-dfe94fc6c8ed","stable_key":"792249b7-a38d-5f43-afb6-2936818a3fa2:tartrazine-azoreductase-ii","predicate":"reduces","statement":"Purified E. coli K12 azoreductase II used tartrazine less efficiently than azoreductase I.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"7d625727-d83c-581a-aa53-1e32fbdbe945","mechanism_event_label":"Purified E. coli K12 azoreductase II used tartrazine less efficiently than azoreductase I.","subject":{"id":"2112c687-03b1-51d6-ade6-25637131f61e","slug":"ecoli-k12-azoreductase-ii-preparation","display_name":"Escherichia coli K12 azoreductase II preparation","entity_type_key":"protein"},"object":{"id":"135b5f4d-0c59-5359-a645-39796e820d42","slug":"tartrazine","display_name":"Tartrazine","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"7d625727-d83c-581a-aa53-1e32fbdbe945","stable_key":"792249b7-a38d-5f43-afb6-2936818a3fa2:tartrazine-azoreductase-ii-event","event_type":"observed_relationship","label":"Purified E. coli K12 azoreductase II used tartrazine less efficiently than azoreductase I.","description":"Purified E. coli K12 azoreductase II used tartrazine less efficiently than azoreductase I.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"2112c687-03b1-51d6-ade6-25637131f61e","slug":"ecoli-k12-azoreductase-ii-preparation","display_name":"Escherichia coli K12 azoreductase II preparation","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"135b5f4d-0c59-5359-a645-39796e820d42","slug":"tartrazine","display_name":"Tartrazine","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"9fbf2e03-16a9-5ca7-965c-0bfc07ca24da","slug":"nadh","display_name":"NADH","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"4aba2a5e-8d06-5304-bb01-c0402b225a94","slug":"nadph","display_name":"NADPH","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"dose","value_text":"Tartrazine among tested substrates; exact substrate/cofactor concentrations unavailable in abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"duration","value_text":"Assay interval unavailable in primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_access","value_text":"Primary PubMed abstract; unrecovered method details explicitly retained.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_scope","value_text":"literature_reviewed; source-specific experimental curation","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified Escherichia coli K12 azoreductases I and II","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Both NADH and NADPH served as electron donors in enzyme characterization. This does not prove that niacin intake controls dye metabolism in humans. Protein genes and tartrazine-specific kinetic constants are unresolved.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Tartrazine food-colorant chapter; nutrient, drug and peptide interactions retain their models and limits.","comparator":null,"unit":null,"notes":"","entity":{"slug":"tartrazine","display_name":"Tartrazine","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Purified Escherichia coli K12 azoreductases I and II","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Purified E. coli K12 azoreductase II used tartrazine less efficiently than azoreductase I.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Purification of two azoreductases from Escherichia coli K12. (1993). https://pubmed.ncbi.nlm.nih.gov/8112774/","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"route","value_text":"In vitro enzyme/substrate incubation","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue","value_text":"Cell-free azo-reduction assays","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"8ff42182-e21c-5ae5-8eb4-8abe4f11f519","evidence_kind":"source_excerpt","locator":"Lines 28-37","start_line":28,"end_line":37,"excerpt":"## tartrazine-azoreductase-ii\nPurified E. coli K12 azoreductase II used tartrazine less efficiently than azoreductase I.\nModel/species: Purified Escherichia coli K12 azoreductases I and II\nTissue: Cell-free azo-reduction assays\nExposure: Tartrazine among tested substrates; exact substrate/cofactor concentrations unavailable in abstract\nRoute: In vitro enzyme/substrate incubation\nDuration: Assay interval unavailable in primary abstract\nLimits: Both NADH and NADPH served as electron donors in enzyme characterization. This does not prove that niacin intake controls dye metabolism in humans. Protein genes and tartrazine-specific kinetic constants are unresolved.\nPrimary reference: Purification of two azoreductases from Escherichia coli K12. (1993). https://pubmed.ncbi.nlm.nih.gov/8112774/\nAccess: Primary PubMed abstract; unrecovered method details explicitly retained.","model_system":"Purified Escherichia coli K12 azoreductases I and II","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Exact original curation span, not a publisher quotation; primary citation retained.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"d9540941-68b4-5a0d-a5c1-828665a918e2","stable_key":"import-792249b7-a38d-5f43-afb6-2936818a3fa2","title":"Tartrazine: mechanisms, molecular forms and cross-actor connections (2026-09-20)","document_type":"imported_text","citation_label":"Original AI-assisted curation of eighteen primary studies. Study-specific citations, negative findings and limitations retained. Not publisher full text.","file_path":"","sha256":"b83a0113a4b743adc91c24504e488f47e10665386b299c4cb0543da8948f4246","revision_id":"3769070e-6af4-5b02-9d8e-f23c84edba1b","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}