{"id":"5679e303-4e96-58df-b07e-70ca13ca79d4","stable_key":"fd37d270-3395-56d6-9f1c-ddda56e606f6:arg-sms-inhibition","predicate":"inhibits","statement":"The product-bound SMS structure supplied a mechanistic explanation for inhibition by methylthioadenosine.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"e10355f1-ded1-5204-b1b5-4c23b617cf21","mechanism_event_label":"A reaction product can slow its own production pathway.","subject":{"id":"525860da-a986-5d19-97f0-a257a454b649","slug":"5-methylthioadenosine","display_name":"5′-Methylthioadenosine","entity_type_key":"small_molecule"},"object":{"id":"0e161cf1-bc45-58f9-9177-05bba899c0bf","slug":"sms","display_name":"Human spermine synthase / SMS","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"e10355f1-ded1-5204-b1b5-4c23b617cf21","stable_key":"fd37d270-3395-56d6-9f1c-ddda56e606f6:arg-sms-inhibition-event","event_type":"observed_relationship","label":"A reaction product can slow its own production pathway.","description":"The product-bound SMS structure supplied a mechanistic explanation for inhibition by methylthioadenosine.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"525860da-a986-5d19-97f0-a257a454b649","slug":"5-methylthioadenosine","display_name":"5′-Methylthioadenosine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"0e161cf1-bc45-58f9-9177-05bba899c0bf","slug":"sms","display_name":"Human spermine synthase / SMS","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"ded80d0b-9076-5034-9e87-cd38f7dafae5","slug":"spermine","display_name":"Spermine","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":"Human SMS structural and biochemical study.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Product inhibition is not a measured dietary-arginine effect.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Arginine collection; tissue, species, dose and formulation distinctions retained.","comparator":null,"unit":null,"notes":"","entity":{"slug":"arginine","display_name":"L-Arginine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A reaction product can slow its own production pathway.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Crystal structure of human spermine synthase: implications of substrate binding and catalytic mechanism. · 2008 · https://pubmed.ncbi.nlm.nih.gov/18367445/ · DOI 10.1074/jbc.m710323200","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"6f367450-0b34-5b35-9e86-bbff373118ba","evidence_kind":"source_excerpt","locator":"Lines 166-172","start_line":166,"end_line":172,"excerpt":"## arg-sms-inhibition\nA reaction product can slow its own production pathway.\nThe product-bound SMS structure supplied a mechanistic explanation for inhibition by methylthioadenosine.\nModel: Human SMS structural and biochemical study.\nLimitations: Product inhibition is not a measured dietary-arginine effect.\nEvidence access: Primary abstract\nCrystal structure of human spermine synthase: implications of substrate binding and catalytic mechanism. · 2008 · https://pubmed.ncbi.nlm.nih.gov/18367445/ · DOI 10.1074/jbc.m710323200","model_system":"Human SMS structural and biochemical study.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; primary evidence access stated per claim.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"bb9a67ea-904f-5b8a-93a4-459081212bdd","stable_key":"import-fd37d270-3395-56d6-9f1c-ddda56e606f6","title":"L-Arginine: transport, metabolic branches, nutrient interactions, availability and discovery questions (2026-09-18)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text.","file_path":"","sha256":"ec0e9a3fb72b7485534e4372a074ac7624a399ff962e55690eb462217b5149ec","revision_id":"af027270-5535-51ae-85ff-9c76c518c962","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}