{"id":"dd110e41-cf13-5d4d-95e4-ca493f960d1a","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:b3-pre-nadsyn-ammonia","predicate":"supports-production-of","statement":"Purified human NADSYN1 also supported NAD+ formation with free ammonia; its reported catalytic efficiencies for glutamine and ammonia were similar, 0.45 and 0.49 per second per millimolar.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"6fad3d2c-7f49-5d54-9713-20b9acf6f28c","mechanism_event_label":"Human NADSYN1 can use either tested nitrogen source in vitro.","subject":{"id":"66894730-4346-5de1-9315-89e683b122e6","slug":"nadsyn1","display_name":"Human glutamine-dependent NAD synthetase / NADSYN1","entity_type_key":"protein"},"object":{"id":"283ed24b-06a1-50aa-9281-df3bac6ce37e","slug":"nad-plus","display_name":"NAD+","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"6fad3d2c-7f49-5d54-9713-20b9acf6f28c","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:b3-pre-nadsyn-ammonia-event","event_type":"biochemical_relationship","label":"Human NADSYN1 can use either tested nitrogen source in vitro.","description":"Purified human NADSYN1 also supported NAD+ formation with free ammonia; its reported catalytic efficiencies for glutamine and ammonia were similar, 0.45 and 0.49 per second per millimolar.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"66894730-4346-5de1-9315-89e683b122e6","slug":"nadsyn1","display_name":"Human glutamine-dependent NAD synthetase / NADSYN1","entity_type_key":"protein"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"8637bb39-2c30-5168-baaf-3e613d831db0","slug":"glutamine","display_name":"L-Glutamine","entity_type_key":"small_molecule"},"role":"compared nitrogen donor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"1374ec24-1a5b-552b-982f-51f9082f4187","slug":"ammonia","display_name":"Ammonia","entity_type_key":"small_molecule"},"role":"alternative nitrogen donor","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"283ed24b-06a1-50aa-9281-df3bac6ce37e","slug":"nad-plus","display_name":"NAD+","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/niacin-precursors-sources/nadsyn2019.paragraphs.txt\", \"locator\": \"Normalized full-text paragraphs 8–8 (0-based)\", \"start_char\": 7090, \"end_char\": 8684, \"file_sha256\": \"36ad82ce734c8e0c44d01c7dc813b1641708738319b53a926e429155b1a602f4\", \"text_sha256\": \"90cb4d2ce3001f2ecf18f1d751db36047726b71a75be94b073474f6f518c96cd\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human NADSYN1 steady-state kinetic assays and crystallography; bacterial comparison kept separate","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Biochemical or structural assay; no dietary intervention","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Assay substrate efficiency does not show that free ammonia replaces glutamine physiologically or justify ammonia exposure.","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":"Human NADSYN1 can use either tested nitrogen source in vitro.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b3-pre-nadsyn2019] Different ways to transport ammonia in human and Mycobacterium tuberculosis NAD+ synthetases. (2020). https://pubmed.ncbi.nlm.nih.gov/31911602/ DOI: 10.1038/s41467-019-13845-4","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified recombinant protein; no intact tissue","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"da7fda34-042e-55ad-8049-a58495273827","evidence_kind":"source_excerpt","locator":"Lines 356-367","start_line":356,"end_line":367,"excerpt":"### b3-pre-nadsyn-ammonia\nPurified human NADSYN1 also supported NAD+ formation with free ammonia; its reported catalytic efficiencies for glutamine and ammonia were similar, 0.45 and 0.49 per second per millimolar.\nCondition category: normal\nnutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Human NADSYN1 can use either tested nitrogen source in vitro.\norganism: Homo sapiens\ntissue_or_cell_type: Purified recombinant protein; no intact tissue\nexperimental_model: Recombinant human NADSYN1 steady-state kinetic assays and crystallography; bacterial comparison kept separate\nlimitations: Assay substrate efficiency does not show that free ammonia replaces glutamine physiologically or justify ammonia exposure.\nexposure: Biochemical or structural assay; no dietary intervention\nevidence_span: {\"source_cache\": \"artifacts/niacin-precursors-sources/nadsyn2019.paragraphs.txt\", \"locator\": \"Normalized full-text paragraphs 8–8 (0-based)\", \"start_char\": 7090, \"end_char\": 8684, \"file_sha256\": \"36ad82ce734c8e0c44d01c7dc813b1641708738319b53a926e429155b1a602f4\", \"text_sha256\": \"90cb4d2ce3001f2ecf18f1d751db36047726b71a75be94b073474f6f518c96cd\"}\n[b3-pre-nadsyn2019] Different ways to transport ammonia in human and Mycobacterium tuberculosis NAD+ synthetases. 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