{"id":"0f2c2074-5543-51d8-9119-3bee3124ab84","stable_key":"f812c44f-d0fd-5f01-ba2c-748c0794fcfb:coumarin-k476e-por","predicate":"reduces_binding_to","statement":"CYP2A6 K476E had lower affinity for NADPH-P450 reductase, contributing to reduced catalytic activity.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"c69fbda2-11cc-524d-9ae1-ebce62db45e3","mechanism_event_label":"A protein change weakened its connection to the electron donor.","subject":{"id":"13baba77-2494-5be0-b6ce-69f3c2c92550","slug":"cyp2a6-k476e","display_name":"Human CYP2A6 K476E experimental variant","entity_type_key":"protein_state"},"object":{"id":"9a730557-ae90-5bf9-a716-c13a6ceef49b","slug":"por","display_name":"NADPH-cytochrome P450 oxidoreductase / POR","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"c69fbda2-11cc-524d-9ae1-ebce62db45e3","stable_key":"f812c44f-d0fd-5f01-ba2c-748c0794fcfb:coumarin-k476e-por-event","event_type":"biochemical_relationship","label":"A protein change weakened its connection to the electron donor.","description":"CYP2A6 K476E had lower affinity for NADPH-P450 reductase, contributing to reduced catalytic activity.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"4aba2a5e-8d06-5304-bb01-c0402b225a94","slug":"nadph","display_name":"NADPH","entity_type_key":"small_molecule"},"role":"electron_source","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"13baba77-2494-5be0-b6ce-69f3c2c92550","slug":"cyp2a6-k476e","display_name":"Human CYP2A6 K476E experimental variant","entity_type_key":"protein_state"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"9a730557-ae90-5bf9-a716-c13a6ceef49b","slug":"por","display_name":"NADPH-cytochrome P450 oxidoreductase / POR","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/coumarin-research/16207711.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"a5f0bef9ac62d55ff5725e8c5cb4eca3e76ef715c758654e76c0c596c52ceab7\", \"start_char\": 0, \"end_char\": 1740, \"text_sha256\": \"a5f0bef9ac62d55ff5725e8c5cb4eca3e76ef715c758654e76c0c596c52ceab7\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Random mutagenesis of recombinant human CYP2A6","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Wild-type enzyme and selected activity-reducing mutants","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Engineered protein dysfunction is not nutrient deficiency; no rescue by nutritional supplementation was tested.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Coumarin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"coumarin","display_name":"Coumarin","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Human engineered protein","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A protein change weakened its connection to the electron donor.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[coumarin-p16207711] Analysis of coumarin 7-hydroxylation activity of cytochrome P450 2A6 using random mutagenesis. (2005). https://pubmed.ncbi.nlm.nih.gov/16207711/ DOI: 10.1074/jbc.m508171200","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Reconstituted enzyme system","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"68ed8cf9-2e0e-5a5f-a41e-6cd66f8b1a7f","evidence_kind":"source_excerpt","locator":"Lines 605-616","start_line":605,"end_line":616,"excerpt":"### coumarin-k476e-por\nCYP2A6 K476E had lower affinity for NADPH-P450 reductase, contributing to reduced catalytic activity.\nCondition category: machinery_impairment\nnutrient_topic: Coumarin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A protein change weakened its connection to the electron donor.\norganism: Human engineered protein\ntissue_or_cell_type: Reconstituted enzyme system\nexperimental_model: Random mutagenesis of recombinant human CYP2A6\nlimitations: Engineered protein dysfunction is not nutrient deficiency; no rescue by nutritional supplementation was tested.\nexposure: Wild-type enzyme and selected activity-reducing mutants\nevidence_span: {\"source_cache\": \"artifacts/coumarin-research/16207711.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"a5f0bef9ac62d55ff5725e8c5cb4eca3e76ef715c758654e76c0c596c52ceab7\", \"start_char\": 0, \"end_char\": 1740, \"text_sha256\": \"a5f0bef9ac62d55ff5725e8c5cb4eca3e76ef715c758654e76c0c596c52ceab7\"}\n[coumarin-p16207711] Analysis of coumarin 7-hydroxylation activity of cytochrome P450 2A6 using random mutagenesis. 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