{"id":"a0d3eef3-d2b3-5407-9369-8e9c2ce894c0","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:b3-redox-slc25a51-precursor-competition-null","predicate":"did_not_compete_detectably","statement":"Excess NMN or nicotinamide did not compete with NAD+ uptake in the isolated-mitochondrial competition assay.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"ae7f0738-ee06-5730-a7a7-a3757f35ae86","mechanism_event_label":"The two precursors did not block the measured NAD import route.","subject":{"id":"d1c59139-db61-5fa0-a25d-40c3e625152e","slug":"nmn","display_name":"NMN","entity_type_key":"small_molecule"},"object":{"id":"aeff3497-d974-5d27-a5fc-27f2c0d5a7d9","slug":"mitochondrial-nad-plus-uptake","display_name":"Mitochondrial NAD+ uptake","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"ae7f0738-ee06-5730-a7a7-a3757f35ae86","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:b3-redox-slc25a51-precursor-competition-null-event","event_type":"biochemical_relationship","label":"The two precursors did not block the measured NAD import route.","description":"Excess NMN or nicotinamide did not compete with NAD+ uptake in the isolated-mitochondrial competition assay.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"08c27a3f-552e-5c92-8688-321a9b64a0d6","slug":"nicotinamide","display_name":"Nicotinamide","entity_type_key":"small_molecule"},"role":"second competitor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"283ed24b-06a1-50aa-9281-df3bac6ce37e","slug":"nad-plus","display_name":"NAD+","entity_type_key":"small_molecule"},"role":"transport substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"8e44149a-f765-546f-a27e-69cc9590e4cf","slug":"slc25a51","display_name":"SLC25A51","entity_type_key":"protein"},"role":"transporter","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"d1c59139-db61-5fa0-a25d-40c3e625152e","slug":"nmn","display_name":"NMN","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"aeff3497-d974-5d27-a5fc-27f2c0d5a7d9","slug":"mitochondrial-nad-plus-uptake","display_name":"Mitochondrial NAD+ uptake","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/niacin-redox-sources/slc25a51-2020.author.txt\", \"locator\": \"Publisher PDF, results; page/figure identified by adjacent text\", \"start_char\": 19115, \"end_char\": 19225, \"file_sha256\": \"8348dbfda6d16d576bb64301f0c75f1488e90e33c4a72213b69756bed21d047d\", \"text_sha256\": \"71f08e5c405c67340bfbe5e1d027cebc9c0f37a2e64bdbd4205020f1ee23e005\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Competition assay with isolated human-cell mitochondria","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Excess precursor alongside NAD+","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Assay-specific negative competition; no assertion that every derivative is excluded from all transporters.","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":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The two precursors did not block the measured NAD import route.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[slc25a51-2020] SLC25A51 is a mammalian mitochondrial NAD+ transporter. (2020). https://pubmed.ncbi.nlm.nih.gov/32906142/ DOI: 10.1038/s41586-020-2741-7","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Mitochondria","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"e231dbf1-2293-5b16-906d-b30e02d15cd1","evidence_kind":"source_excerpt","locator":"Lines 1081-1092","start_line":1081,"end_line":1092,"excerpt":"### b3-redox-slc25a51-precursor-competition-null\nExcess NMN or nicotinamide did not compete with NAD+ uptake in the isolated-mitochondrial competition assay.\nCondition category: normal\nnutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The two precursors did not block the measured NAD import route.\norganism: Homo sapiens\ntissue_or_cell_type: Mitochondria\nexperimental_model: Competition assay with isolated human-cell mitochondria\nlimitations: Assay-specific negative competition; no assertion that every derivative is excluded from all transporters.\nexposure: Excess precursor alongside NAD+\nevidence_span: {\"source_cache\": \"artifacts/niacin-redox-sources/slc25a51-2020.author.txt\", \"locator\": \"Publisher PDF, results; page/figure identified by adjacent text\", \"start_char\": 19115, \"end_char\": 19225, \"file_sha256\": \"8348dbfda6d16d576bb64301f0c75f1488e90e33c4a72213b69756bed21d047d\", \"text_sha256\": \"71f08e5c405c67340bfbe5e1d027cebc9c0f37a2e64bdbd4205020f1ee23e005\"}\n[slc25a51-2020] SLC25A51 is a mammalian mitochondrial NAD+ transporter. (2020). https://pubmed.ncbi.nlm.nih.gov/32906142/ DOI: 10.1038/s41586-020-2741-7","model_system":"Competition assay with isolated human-cell mitochondria","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [slc25a51-2020] SLC25A51 is a mammalian mitochondrial NAD+ transporter. (2020). https://pubmed.ncbi.nlm.nih.gov/32906142/ DOI: 10.1038/s41586-020-2741-7","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"a62b7b5b-786a-57e9-85e9-67c6912a5054","stable_key":"import-a9dd23c6-978a-5755-8bd8-f29bd1fe0cda","title":"Niacin: NAD metabolism, deficiency and nutrient interactions (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":"a8cac59639322f74812ce12eef338c2f6c385c04cc4af6ab511fc7c972f0c2e6","revision_id":"bec8fc45-12e7-5f75-a814-5d72ed015d01","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}