{"id":"1de87c80-88d3-5b95-bd45-c27ca39e2c91","stable_key":"63ce713e-6aea-59f6-9896-ca30e010b2ce:l-tyrosine-tat-discrimination","predicate":"discriminates_against","statement":"Human TAT catalytic efficiency for tyrosine was about four orders of magnitude greater than for phenylalanine.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"e3f40b3c-ad50-5f60-8d25-e35de1be59a2","mechanism_event_label":"Closely related amino acids are not interchangeable substrates.","subject":{"id":"f4bcff80-2f4b-5295-a5fa-14e2d6720ec9","slug":"tat","display_name":"Human tyrosine aminotransferase / TAT","entity_type_key":"protein"},"object":{"id":"190407ad-0219-54b5-b05f-7c75f3895ca6","slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"e3f40b3c-ad50-5f60-8d25-e35de1be59a2","stable_key":"63ce713e-6aea-59f6-9896-ca30e010b2ce:l-tyrosine-tat-discrimination-event","event_type":"observed_relationship","label":"Closely related amino acids are not interchangeable substrates.","description":"Human TAT catalytic efficiency for tyrosine was about four orders of magnitude greater than for phenylalanine.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"f4bcff80-2f4b-5295-a5fa-14e2d6720ec9","slug":"tat","display_name":"Human tyrosine aminotransferase / TAT","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"190407ad-0219-54b5-b05f-7c75f3895ca6","slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"},"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":"Purified human enzyme substrate comparison.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This finding does not support TAT as an effective substitute for deficient PAH.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Tyrosine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-tyrosine","display_name":"L-Tyrosine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Closely related amino acids are not interchangeable substrates.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"The narrow substrate specificity of human tyrosine aminotransferase--the enzyme deficient in tyrosinemia type II. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16640556/ · DOI 10.1111/j.1742-4658.2006.05202.x","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"9a1fe970-6160-5eb9-bdab-bc6fb20c3686","evidence_kind":"source_excerpt","locator":"Lines 220-226","start_line":220,"end_line":226,"excerpt":"## l-tyrosine-tat-discrimination\nClosely related amino acids are not interchangeable substrates.\nHuman TAT catalytic efficiency for tyrosine was about four orders of magnitude greater than for phenylalanine.\nModel: Purified human enzyme substrate comparison.\nLimitations: This finding does not support TAT as an effective substitute for deficient PAH.\nEvidence access: Primary abstract\nThe narrow substrate specificity of human tyrosine aminotransferase--the enzyme deficient in tyrosinemia type II. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16640556/ · DOI 10.1111/j.1742-4658.2006.05202.x","model_system":"Purified human enzyme substrate comparison.","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":"12917df2-c6e0-5b61-850f-dbff6d4b4d30","stable_key":"import-63ce713e-6aea-59f6-9896-ca30e010b2ce","title":"L-Tyrosine: catecholamines, thyroid chemistry, pigment, metabolism 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. Not publisher full text.","file_path":"","sha256":"7777f4440a8bfb14a04ff73e73392ccc45d8ee89f7853ecbcc0027d6f563b8a0","revision_id":"e1206111-3a75-5809-b8e9-231ff809ff1e","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}