{"id":"588f7e8a-2552-588b-a228-66186236dd64","stable_key":"88eb7407-f147-558b-889b-0c89c4e0aa4a:spermidine-dhps-binding","predicate":"binds","statement":"The human DHPS study measured an apparent spermidine binding KD of about 4 micromolar using the reported FRET assay.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"ec38dc4e-512d-5870-810c-39e6996eba02","mechanism_event_label":"The first enzyme recognizes spermidine directly.","subject":{"id":"7014993c-468f-5c6b-ab04-80c87f9dfd9f","slug":"spermidine","display_name":"Spermidine","entity_type_key":"small_molecule"},"object":{"id":"33684e20-5166-55d6-9196-0793156787f1","slug":"dhps","display_name":"DHPS","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"ec38dc4e-512d-5870-810c-39e6996eba02","stable_key":"88eb7407-f147-558b-889b-0c89c4e0aa4a:spermidine-dhps-binding-event","event_type":"observed_relationship","label":"The first enzyme recognizes spermidine directly.","description":"The human DHPS study measured an apparent spermidine binding KD of about 4 micromolar using the reported FRET assay.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"7014993c-468f-5c6b-ab04-80c87f9dfd9f","slug":"spermidine","display_name":"Spermidine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"33684e20-5166-55d6-9196-0793156787f1","slug":"dhps","display_name":"DHPS","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full text","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human DHPS; assay-dependent apparent affinity.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Binding affinity is not a dietary requirement, plasma target or treatment dose.","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":"The first enzyme recognizes spermidine directly.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Half Way to Hypusine-Structural Basis for Substrate Recognition by Human Deoxyhypusine Synthase. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32235505/ · DOI 10.3390/biom10040522","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"47c71d94-7a23-5fda-b74d-6a41684321f8","evidence_kind":"source_excerpt","locator":"Lines 22-28","start_line":22,"end_line":28,"excerpt":"## spermidine-dhps-binding\nThe first enzyme recognizes spermidine directly.\nThe human DHPS study measured an apparent spermidine binding KD of about 4 micromolar using the reported FRET assay.\nModel: Recombinant human DHPS; assay-dependent apparent affinity.\nLimitations: Binding affinity is not a dietary requirement, plasma target or treatment dose.\nEvidence access: Primary full text\nHalf Way to Hypusine-Structural Basis for Substrate Recognition by Human Deoxyhypusine Synthase. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32235505/ · DOI 10.3390/biom10040522","model_system":"Recombinant human DHPS; assay-dependent apparent affinity.","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. Not publisher full text.","file_path":"","sha256":"8eec8784bc2bd0384cfd53c6603c4ced8e53c227d9ab29ed85594c43e34c68ef","revision_id":"7c421a18-4526-59f6-b84e-4be533bc35ac","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}