{"id":"03d7f22c-c9ef-5bdf-9fd4-8c917b6e2984","stable_key":"56f1d914-e7da-595a-af69-c217b2b47407:l-phenylalanine-pah-conversion","predicate":"hydroxylates","statement":"PAH catalyzes phenylalanine hydroxylation to tyrosine using BH4, molecular oxygen and non-heme ferrous iron.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"e560642b-caad-549e-9364-aea98e9702e2","mechanism_event_label":"Making tyrosine requires a working enzyme and its chemical helpers.","subject":{"id":"ea908671-6f85-5342-abe4-1a466a3b0572","slug":"pah","display_name":"Human phenylalanine hydroxylase / PAH","entity_type_key":"protein"},"object":{"id":"bcfef85f-831d-5439-ba51-1aef4b090441","slug":"l-tyrosine","display_name":"L-Tyrosine","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"e560642b-caad-549e-9364-aea98e9702e2","stable_key":"56f1d914-e7da-595a-af69-c217b2b47407:l-phenylalanine-pah-conversion-event","event_type":"observed_relationship","label":"Making tyrosine requires a working enzyme and its chemical helpers.","description":"PAH catalyzes phenylalanine hydroxylation to tyrosine using BH4, molecular oxygen and non-heme ferrous iron.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"ea908671-6f85-5342-abe4-1a466a3b0572","slug":"pah","display_name":"Human phenylalanine hydroxylase / PAH","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"bcfef85f-831d-5439-ba51-1aef4b090441","slug":"l-tyrosine","display_name":"L-Tyrosine","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"190407ad-0219-54b5-b05f-7c75f3895ca6","slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"1c231b90-c106-507a-8766-870ecb40e368","slug":"tetrahydrobiopterin","display_name":"Tetrahydrobiopterin / BH4","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full text; reaction background distinguished from new structural experiments","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human PAH structural study; established reaction described in the full-text introduction.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This record describes the established reaction, not a new dietary intervention or a human iron-deficiency threshold.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Phenylalanine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Making tyrosine requires a working enzyme and its chemical helpers.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Structural basis for ligand-dependent dimerization of phenylalanine hydroxylase regulatory domain. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27049649/ · DOI 10.1038/srep23748","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"2f2773f1-e71d-50a0-b51e-4418ff52f986","evidence_kind":"source_excerpt","locator":"Lines 14-20","start_line":14,"end_line":20,"excerpt":"## l-phenylalanine-pah-conversion\nMaking tyrosine requires a working enzyme and its chemical helpers.\nPAH catalyzes phenylalanine hydroxylation to tyrosine using BH4, molecular oxygen and non-heme ferrous iron.\nModel: Human PAH structural study; established reaction described in the full-text introduction.\nLimitations: This record describes the established reaction, not a new dietary intervention or a human iron-deficiency threshold.\nEvidence access: Primary full text; reaction background distinguished from new structural experiments\nStructural basis for ligand-dependent dimerization of phenylalanine hydroxylase regulatory domain. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27049649/ · DOI 10.1038/srep23748","model_system":"Human PAH structural study; established reaction described in the full-text introduction.","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":"54de7c56-1e60-5d7b-8ef9-852c58ae92ba","stable_key":"import-56f1d914-e7da-595a-af69-c217b2b47407","title":"L-Phenylalanine: transport, protein synthesis, cofactor recycling 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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