{"id":"8f9c939c-0252-5e74-9946-bca9bcc2b114","stable_key":"56f1d914-e7da-595a-af69-c217b2b47407:l-phenylalanine-no-tyrosine-requirement","predicate":"supports","statement":"A tracer study in healthy Indian adults consuming no tyrosine estimated mean phenylalanine requirement at about 38 mg/kg/day.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"f727ef95-7716-5547-adab-8dbb61f861d4","mechanism_event_label":"When tyrosine is absent, phenylalanine must cover an additional metabolic demand.","subject":{"id":"190407ad-0219-54b5-b05f-7c75f3895ca6","slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"},"object":{"id":"af82b147-62ec-5dd8-ab4c-461e8a79ccff","slug":"human-phenylalanine-requirement","display_name":"Human dietary phenylalanine requirement estimate","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"f727ef95-7716-5547-adab-8dbb61f861d4","stable_key":"56f1d914-e7da-595a-af69-c217b2b47407:l-phenylalanine-no-tyrosine-requirement-event","event_type":"observed_relationship","label":"When tyrosine is absent, phenylalanine must cover an additional metabolic demand.","description":"A tracer study in healthy Indian adults consuming no tyrosine estimated mean phenylalanine requirement at about 38 mg/kg/day.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"190407ad-0219-54b5-b05f-7c75f3895ca6","slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"af82b147-62ec-5dd8-ab4c-461e8a79ccff","slug":"human-phenylalanine-requirement","display_name":"Human dietary phenylalanine requirement estimate","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"bcfef85f-831d-5439-ba51-1aef4b090441","slug":"l-tyrosine","display_name":"L-Tyrosine","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 indicator amino-acid oxidation/balance feeding study without dietary tyrosine.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Population and protocol differ from the older-adult excess-tyrosine study; different estimates are not treated as a scientific contradiction.","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":"When tyrosine is absent, phenylalanine must cover an additional metabolic demand.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"The daily phenylalanine requirement of healthy Indian adults. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16762944/ · DOI 10.1093/ajcn/83.6.1331","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"2e41c37a-7001-5cb3-83d0-033c667f5087","evidence_kind":"source_excerpt","locator":"Lines 270-276","start_line":270,"end_line":276,"excerpt":"## l-phenylalanine-no-tyrosine-requirement\nWhen tyrosine is absent, phenylalanine must cover an additional metabolic demand.\nA tracer study in healthy Indian adults consuming no tyrosine estimated mean phenylalanine requirement at about 38 mg/kg/day.\nModel: Human indicator amino-acid oxidation/balance feeding study without dietary tyrosine.\nLimitations: Population and protocol differ from the older-adult excess-tyrosine study; different estimates are not treated as a scientific contradiction.\nEvidence access: Primary abstract\nThe daily phenylalanine requirement of healthy Indian adults. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16762944/ · DOI 10.1093/ajcn/83.6.1331","model_system":"Human indicator amino-acid oxidation/balance feeding study without dietary tyrosine.","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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