{"id":"3b774bc2-8fd8-5012-be8e-0af58f376a12","stable_key":"88eb7407-f147-558b-889b-0c89c4e0aa4a:spermidine-sat1-cosubstrate","predicate":"acetyl_donor_for","statement":"Human SAT1 kinetics support a random sequential mechanism involving acetyl donor and polyamine in a ternary complex.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"055dd583-bf7a-5d37-8a20-8eaa2871e0cd","mechanism_event_label":"Both the donor and the polyamine must reach the enzyme.","subject":{"id":"b7ed6e4c-e560-5cee-b68f-895f21862e6f","slug":"acetyl-coa","display_name":"Acetyl-CoA","entity_type_key":"small_molecule"},"object":{"id":"3763e5e6-9a10-5a6a-a39c-8c53fc190002","slug":"sat1","display_name":"Human spermidine/spermine N1-acetyltransferase / SAT1","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"055dd583-bf7a-5d37-8a20-8eaa2871e0cd","stable_key":"88eb7407-f147-558b-889b-0c89c4e0aa4a:spermidine-sat1-cosubstrate-event","event_type":"observed_relationship","label":"Both the donor and the polyamine must reach the enzyme.","description":"Human SAT1 kinetics support a random sequential mechanism involving acetyl donor and polyamine in a ternary complex.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"b7ed6e4c-e560-5cee-b68f-895f21862e6f","slug":"acetyl-coa","display_name":"Acetyl-CoA","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"3763e5e6-9a10-5a6a-a39c-8c53fc190002","slug":"sat1","display_name":"Human spermidine/spermine N1-acetyltransferase / SAT1","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"7014993c-468f-5c6b-ab04-80c87f9dfd9f","slug":"spermidine","display_name":"Spermidine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"69481d06-17fc-50ee-87f6-81c958322f65","slug":"n1-acetylspermidine","display_name":"N1-Acetylspermidine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human SAT1 initial-velocity, inhibition and pH experiments.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Mechanism does not quantify whole-body acetyl-CoA competition.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Spermidine collection; molecular form, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"spermidine","display_name":"Spermidine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Both the donor and the polyamine must reach the enzyme.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Mechanistic and structural analysis of human spermidine/spermine N1-acetyltransferase. · 2007 · https://pubmed.ncbi.nlm.nih.gov/17516632/ · DOI 10.1021/bi700256z","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"6170077c-ae3e-5f87-8ffa-ea237a67e6d6","evidence_kind":"source_excerpt","locator":"Lines 86-92","start_line":86,"end_line":92,"excerpt":"## spermidine-sat1-cosubstrate\nBoth the donor and the polyamine must reach the enzyme.\nHuman SAT1 kinetics support a random sequential mechanism involving acetyl donor and polyamine in a ternary complex.\nModel: Human SAT1 initial-velocity, inhibition and pH experiments.\nLimitations: Mechanism does not quantify whole-body acetyl-CoA competition.\nEvidence access: Primary abstract\nMechanistic and structural analysis of human spermidine/spermine N1-acetyltransferase. · 2007 · https://pubmed.ncbi.nlm.nih.gov/17516632/ · DOI 10.1021/bi700256z","model_system":"Human SAT1 initial-velocity, inhibition and pH experiments.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"4348f3f8-0180-58a3-b61c-55d03bb322d2","stable_key":"import-88eb7407-f147-558b-889b-0c89c4e0aa4a","title":"Spermidine: biosynthesis, hypusination, transport and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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