{"id":"492d6a85-a5d3-55a8-8fb1-3c317a56ba59","stable_key":"584c58f5-ab9f-53f3-97a9-55783db943b0:tryptophan-ido-ring-cleavage","predicate":"catalyzes_formation","statement":"Human IDO1 uses heme-bound oxygen to cleave the tryptophan indole ring, incorporating both oxygen atoms during N-formylkynurenine formation.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"72abea9f-21e3-5482-8eb1-3bcb474a2a09","mechanism_event_label":"An immune-regulated enzyme opens a different route for tryptophan.","subject":{"id":"9edba4aa-c2f5-5a4e-9750-15e9a38b1822","slug":"ido1","display_name":"Human indoleamine 2,3-dioxygenase 1 / IDO1","entity_type_key":"protein"},"object":{"id":"540784df-850e-5eac-a71c-22556535e471","slug":"n-formylkynurenine","display_name":"N-Formyl-L-kynurenine","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"72abea9f-21e3-5482-8eb1-3bcb474a2a09","stable_key":"584c58f5-ab9f-53f3-97a9-55783db943b0:tryptophan-ido-ring-cleavage-event","event_type":"observed_relationship","label":"An immune-regulated enzyme opens a different route for tryptophan.","description":"Human IDO1 uses heme-bound oxygen to cleave the tryptophan indole ring, incorporating both oxygen atoms during N-formylkynurenine formation.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"9edba4aa-c2f5-5a4e-9750-15e9a38b1822","slug":"ido1","display_name":"Human indoleamine 2,3-dioxygenase 1 / IDO1","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"540784df-850e-5eac-a71c-22556535e471","slug":"n-formylkynurenine","display_name":"N-Formyl-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":"2e1f7e0a-8b54-5ea3-9d34-01e7167f9097","slug":"heme","display_name":"Heme","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 IDO1 structure and mutagenesis.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Catalytic heme dependence does not establish benefit from extra dietary iron.","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":"An immune-regulated enzyme opens a different route for tryptophan.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Crystal structure of human indoleamine 2,3-dioxygenase: catalytic mechanism of O2 incorporation by a heme-containing dioxygenase. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16477023/ · DOI 10.1073/pnas.0508996103","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"0c814dbb-2c62-5947-aa9a-f2f1cd13428d","evidence_kind":"source_excerpt","locator":"Lines 170-176","start_line":170,"end_line":176,"excerpt":"## tryptophan-ido-ring-cleavage\nAn immune-regulated enzyme opens a different route for tryptophan.\nHuman IDO1 uses heme-bound oxygen to cleave the tryptophan indole ring, incorporating both oxygen atoms during N-formylkynurenine formation.\nModel: Human IDO1 structure and mutagenesis.\nLimitations: Catalytic heme dependence does not establish benefit from extra dietary iron.\nEvidence access: Primary abstract\nCrystal structure of human indoleamine 2,3-dioxygenase: catalytic mechanism of O2 incorporation by a heme-containing dioxygenase. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16477023/ · DOI 10.1073/pnas.0508996103","model_system":"Human IDO1 structure and mutagenesis.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; 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