{"id":"cc776638-803c-581b-8465-dbe9ab9d74a8","stable_key":"88eb7407-f147-558b-889b-0c89c4e0aa4a:spermidine-hydroxylation-lock","predicate":"resists_dhps_reversal","statement":"The same reversal assay did not remove the side chain from hypusine-containing eIF5A.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"69833043-ab01-5350-b4a8-27d9bad2e5ad","mechanism_event_label":"The second modification step stabilizes the completed product.","subject":{"id":"fd7586aa-2477-5fbf-b715-1fd83e0c5483","slug":"eif5a1-hypusine","display_name":"eIF5A1 with hypusine at residue 50","entity_type_key":"protein_state"},"object":{"id":"33684e20-5166-55d6-9196-0793156787f1","slug":"dhps","display_name":"DHPS","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"69833043-ab01-5350-b4a8-27d9bad2e5ad","stable_key":"88eb7407-f147-558b-889b-0c89c4e0aa4a:spermidine-hydroxylation-lock-event","event_type":"observed_relationship","label":"The second modification step stabilizes the completed product.","description":"The same reversal assay did not remove the side chain from hypusine-containing eIF5A.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"fd7586aa-2477-5fbf-b715-1fd83e0c5483","slug":"eif5a1-hypusine","display_name":"eIF5A1 with hypusine at residue 50","entity_type_key":"protein_state"},"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":""},{"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":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified human DHPS comparison of deoxyhypusine and hypusine protein substrates.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Assay-specific non-reversal does not establish lifetime stability of the protein.","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 second modification step stabilizes the completed product.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Reversal of the deoxyhypusine synthesis reaction. Generation of spermidine or homospermidine from deoxyhypusine by deoxyhypusine synthase. · 2003 · https://pubmed.ncbi.nlm.nih.gov/12788913/ · DOI 10.1074/jbc.M304247200","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"b4333afe-5b65-5f24-9c91-acc3e2c8e27d","evidence_kind":"source_excerpt","locator":"Lines 46-52","start_line":46,"end_line":52,"excerpt":"## spermidine-hydroxylation-lock\nThe second modification step stabilizes the completed product.\nThe same reversal assay did not remove the side chain from hypusine-containing eIF5A.\nModel: Purified human DHPS comparison of deoxyhypusine and hypusine protein substrates.\nLimitations: Assay-specific non-reversal does not establish lifetime stability of the protein.\nEvidence access: Primary abstract\nReversal of the deoxyhypusine synthesis reaction. Generation of spermidine or homospermidine from deoxyhypusine by deoxyhypusine synthase. · 2003 · https://pubmed.ncbi.nlm.nih.gov/12788913/ · DOI 10.1074/jbc.M304247200","model_system":"Purified human DHPS comparison of deoxyhypusine and hypusine protein substrates.","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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