{"id":"41099a7c-ea34-5c8c-a391-58627f98b07f","stable_key":"584c58f5-ab9f-53f3-97a9-55783db943b0:tryptophan-afmid-triad","predicate":"mutations_disable","statement":"S162A, D247A or H279A substitutions in mouse Afmid each removed more than 99% of measured enzyme activity.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"85164a64-c577-5b8b-87e5-db0f910b2832","mechanism_event_label":"One defective catalytic residue can block the next step despite available substrate.","subject":{"id":"1061b155-e24c-5159-a052-40b3e78bdc00","slug":"mouse-afmid","display_name":"Mouse arylformamidase / Afmid","entity_type_key":"protein"},"object":{"id":"ce72cbd6-7077-5f23-a859-a8000a3f8194","slug":"kynurenine","display_name":"L-Kynurenine","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"85164a64-c577-5b8b-87e5-db0f910b2832","stable_key":"584c58f5-ab9f-53f3-97a9-55783db943b0:tryptophan-afmid-triad-event","event_type":"observed_relationship","label":"One defective catalytic residue can block the next step despite available substrate.","description":"S162A, D247A or H279A substitutions in mouse Afmid each removed more than 99% of measured enzyme activity.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"1061b155-e24c-5159-a052-40b3e78bdc00","slug":"mouse-afmid","display_name":"Mouse arylformamidase / Afmid","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"ce72cbd6-7077-5f23-a859-a8000a3f8194","slug":"kynurenine","display_name":"L-Kynurenine","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"769339cb-213b-559e-acc0-07ed00368b94","slug":"l-tryptophan","display_name":"L-Tryptophan","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"540784df-850e-5eac-a71c-22556535e471","slug":"n-formylkynurenine","display_name":"N-Formyl-L-kynurenine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant mouse enzyme mutations.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Does not quantify human variant effects or prove a clinical repletion failure.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-tryptophan","display_name":"L-Tryptophan","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"One defective catalytic residue can block the next step despite available substrate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Cloning, expression, and catalytic triad of recombinant arylformamidase. · 2005 · https://pubmed.ncbi.nlm.nih.gov/15935693/ · DOI 10.1016/j.pep.2005.04.013","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"ed42eb0e-0831-5522-9ba1-89b3fbfb7f0d","evidence_kind":"source_excerpt","locator":"Lines 194-200","start_line":194,"end_line":200,"excerpt":"## tryptophan-afmid-triad\nOne defective catalytic residue can block the next step despite available substrate.\nS162A, D247A or H279A substitutions in mouse Afmid each removed more than 99% of measured enzyme activity.\nModel: Recombinant mouse enzyme mutations.\nLimitations: Does not quantify human variant effects or prove a clinical repletion failure.\nEvidence access: Primary abstract\nCloning, expression, and catalytic triad of recombinant arylformamidase. · 2005 · https://pubmed.ncbi.nlm.nih.gov/15935693/ · DOI 10.1016/j.pep.2005.04.013","model_system":"Recombinant mouse enzyme mutations.","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":"73f9d3e7-fdc9-5418-8f3c-f4ef145f6efa","stable_key":"import-584c58f5-ab9f-53f3-97a9-55783db943b0","title":"Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary-abstract references and experimental limitations individually identified. 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