{"id":"66e93bc6-3d6a-5c0f-b4ab-87d00f1d4907","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:b3-cons-mna-stability","predicate":"shows_limited_turnover","statement":"After 24 hours of labeled N1-methylnicotinamide exposure, cancer-cell tracing did not detect conversion to other labeled metabolites.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"f78e2359-ea0d-5e69-a5e5-73c3b58faaa5","mechanism_event_label":"The methylated product was relatively stable during this cell-culture experiment.","subject":{"id":"b02a63e0-a972-53c5-8a3a-eea6b7578cd5","slug":"n1-methylnicotinamide","display_name":"N1-Methylnicotinamide","entity_type_key":"small_molecule"},"object":{"id":"30023712-7323-5f4a-bf08-12561224607c","slug":"n1-methylnicotinamide-turnover","display_name":"N1-Methylnicotinamide turnover","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"f78e2359-ea0d-5e69-a5e5-73c3b58faaa5","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:b3-cons-mna-stability-event","event_type":"observed_intervention","label":"The methylated product was relatively stable during this cell-culture experiment.","description":"After 24 hours of labeled N1-methylnicotinamide exposure, cancer-cell tracing did not detect conversion to other labeled metabolites.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"b02a63e0-a972-53c5-8a3a-eea6b7578cd5","slug":"n1-methylnicotinamide","display_name":"N1-Methylnicotinamide","entity_type_key":"small_molecule"},"role":"tracer_substrate","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"30023712-7323-5f4a-bf08-12561224607c","slug":"n1-methylnicotinamide-turnover","display_name":"N1-Methylnicotinamide turnover","entity_type_key":"cellular_process"},"role":"outcome","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"true","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/niacin-consumption-sources/nnmt2013.txt\", \"locator\": \"Full text, normalized paragraph 33\", \"start_char\": 18035, \"end_char\": 19275, \"file_sha256\": \"7d88fd656ba772962185234a9bd021e40a9b83f9156db836f723eba06b68acca\", \"text_sha256\": \"efcd23e962441fae2b1fb3602db6a6d820ad2d17a511651b3950a2499df2fa02\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Deuterated metabolite tracing and LC-MS","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Deuterated N1-methylnicotinamide for 24 hours; labeled nicotinamide comparison","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Engineered human cancer-cell culture, not healthy-human niacin repletion. SAM consumption does not establish systemic methyl depletion or a need for folate/B12 supplements. Non-detection is assay-limited and does not establish absolute irreversibility or whole-body clearance.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Niacin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"niacin","display_name":"Niacin (vitamin B3)","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Human","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The methylated product was relatively stable during this cell-culture experiment.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b3-cons-nnmt2013] NNMT promotes epigenetic remodeling in cancer by creating a metabolic methylation sink. (2013). https://pubmed.ncbi.nlm.nih.gov/23455543/ DOI: 10.1038/nchembio.1204","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human 769P renal carcinoma cells","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"1d340764-5217-5b14-ac4b-01c138a45873","evidence_kind":"source_excerpt","locator":"Lines 817-829","start_line":817,"end_line":829,"excerpt":"### b3-cons-mna-stability\nAfter 24 hours of labeled N1-methylnicotinamide exposure, cancer-cell tracing did not detect conversion to other labeled metabolites.\nCondition category: normal\nnutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The methylated product was relatively stable during this cell-culture experiment.\norganism: Human\ntissue_or_cell_type: Human 769P renal carcinoma cells\nexperimental_model: Deuterated metabolite tracing and LC-MS\nlimitations: Engineered human cancer-cell culture, not healthy-human niacin repletion. SAM consumption does not establish systemic methyl depletion or a need for folate/B12 supplements. Non-detection is assay-limited and does not establish absolute irreversibility or whole-body clearance.\nexposure: Deuterated N1-methylnicotinamide for 24 hours; labeled nicotinamide comparison\ncross_nutrient: true\nevidence_span: {\"source_cache\": \"artifacts/niacin-consumption-sources/nnmt2013.txt\", \"locator\": \"Full text, normalized paragraph 33\", \"start_char\": 18035, \"end_char\": 19275, \"file_sha256\": \"7d88fd656ba772962185234a9bd021e40a9b83f9156db836f723eba06b68acca\", \"text_sha256\": \"efcd23e962441fae2b1fb3602db6a6d820ad2d17a511651b3950a2499df2fa02\"}\n[b3-cons-nnmt2013] NNMT promotes epigenetic remodeling in cancer by creating a metabolic methylation sink. 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