{"id":"40a99b15-5709-5719-a1d6-02bf1b036cc0","stable_key":"c3df3634-4c3a-5099-a5d9-e4f6344c1084:sirt1-h4k16-deacetylation","predicate":"deacetylates","statement":"Human SIRT1 removes acetylation from histone H4 Lys16 in an NAD+-dependent reaction.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"0e3449f5-04ee-5ed5-9c75-ffb8330f0bf2","mechanism_event_label":"A different enzyme removes a lysine modification using NAD+.","subject":{"id":"b8e1bfa9-c412-5f35-97af-cfc722123d27","slug":"sirt1","display_name":"SIRT1","entity_type_key":"protein"},"object":{"id":"fba9b635-5181-5b2a-87dd-cdc67afa0acd","slug":"h4k16ac","display_name":"Histone H4 acetylated at K16","entity_type_key":"protein_state"},"evidence_count":1,"mechanism_event":{"id":"0e3449f5-04ee-5ed5-9c75-ffb8330f0bf2","stable_key":"c3df3634-4c3a-5099-a5d9-e4f6344c1084:sirt1-h4k16-deacetylation-event","event_type":"biochemical_relationship","label":"A different enzyme removes a lysine modification using NAD+.","description":"Human SIRT1 removes acetylation from histone H4 Lys16 in an NAD+-dependent reaction.","status":"provisional","compartment":{"slug":"nucleus","display_name":"Nucleus"},"participants":[{"entity":{"id":"b8e1bfa9-c412-5f35-97af-cfc722123d27","slug":"sirt1","display_name":"SIRT1","entity_type_key":"protein"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"fba9b635-5181-5b2a-87dd-cdc67afa0acd","slug":"h4k16ac","display_name":"Histone H4 acetylated at K16","entity_type_key":"protein_state"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"389a022a-4f27-548a-ad0a-649904aa1851","slug":"h4k16","display_name":"Histone H4 unacetylated at K16","entity_type_key":"protein_state"},"role":"product","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":"cosubstrate","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"08c27a3f-552e-5c92-8688-321a9b64a0d6","slug":"nicotinamide","display_name":"Nicotinamide","entity_type_key":"small_molecule"},"role":"coproduct","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"e51e5546-5ace-5717-a7c1-64f3adaed6d9","slug":"o-acetyl-adp-ribose","display_name":"O-Acetyl-ADP-ribose","entity_type_key":"small_molecule"},"role":"coproduct","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Human enzyme assays and cultured-cell SIRT1 perturbation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This reaction modifies lysine already in a protein. It does not show that extra oral lysine increases the reaction or improves a clinical outcome.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"organism","value_text":"Human","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A different enzyme removes a lysine modification using NAD+.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[sirt1-2004] Human SirT1 interacts with histone H1 and promotes formation of facultative heterochromatin (2004). https://pubmed.ncbi.nlm.nih.gov/15469825/ DOI: 10.1016/j.molcel.2004.08.031","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Not specified as a whole tissue; see experimental model.","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"4bfbe13f-a793-5c9e-ad39-06c0ced50fb6","evidence_kind":"source_excerpt","locator":"Lines 537-545","start_line":537,"end_line":545,"excerpt":"### sirt1-h4k16-deacetylation\nHuman SIRT1 removes acetylation from histone H4 Lys16 in an NAD+-dependent reaction.\nPlain language: A different enzyme removes a lysine modification using NAD+.\nCondition category: normal\norganism: Human\ntissue_or_cell_type: Not specified as a whole tissue; see experimental model.\nexperimental_model: Human enzyme assays and cultured-cell SIRT1 perturbation.\nlimitations: This reaction modifies lysine already in a protein. It does not show that extra oral lysine increases the reaction or improves a clinical outcome.\n[sirt1-2004] Human SirT1 interacts with histone H1 and promotes formation of facultative heterochromatin (2004). https://pubmed.ncbi.nlm.nih.gov/15469825/ DOI: 10.1016/j.molcel.2004.08.031","model_system":"Human enzyme assays and cultured-cell SIRT1 perturbation.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact quote from the accompanying curation document, not from publisher text. Original study references: [sirt1-2004] Human SirT1 interacts with histone H1 and promotes formation of facultative heterochromatin (2004). https://pubmed.ncbi.nlm.nih.gov/15469825/ DOI: 10.1016/j.molcel.2004.08.031","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"7633bde7-dcc9-5086-91c6-a45eb96857f3","stable_key":"import-c3df3634-4c3a-5099-a5d9-e4f6344c1084","title":"L-Lysine: mechanism-first literature curation (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":"93998d47c21525409ba82f1c82ededf2893dff15fbe61c7deffc175b0e298e97","revision_id":"3897e31f-6624-59e1-a053-8a81b7361632","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}