{"id":"86077744-ab4a-5dee-8190-f380f6c4320d","stable_key":"63ce713e-6aea-59f6-9896-ca30e010b2ce:l-tyrosine-hpd-hga","predicate":"produces","statement":"Human HPD converts 4-hydroxyphenylpyruvate to homogentisate; substrate-binding-site mutations altered catalytic efficiency.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"1d8a8bc0-3e74-5860-b756-69e83aebdd19","mechanism_event_label":"The carbon skeleton passes through a separate oxygen-dependent enzyme.","subject":{"id":"9aabe27f-74c1-5758-8ac1-0105cbddb5f1","slug":"hpd","display_name":"Human 4-hydroxyphenylpyruvate dioxygenase / HPD","entity_type_key":"protein"},"object":{"id":"ea7ed42c-7c9f-5d5a-912a-7b67e60df93e","slug":"homogentisate","display_name":"Homogentisate","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"1d8a8bc0-3e74-5860-b756-69e83aebdd19","stable_key":"63ce713e-6aea-59f6-9896-ca30e010b2ce:l-tyrosine-hpd-hga-event","event_type":"observed_relationship","label":"The carbon skeleton passes through a separate oxygen-dependent enzyme.","description":"Human HPD converts 4-hydroxyphenylpyruvate to homogentisate; substrate-binding-site mutations altered catalytic efficiency.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"9aabe27f-74c1-5758-8ac1-0105cbddb5f1","slug":"hpd","display_name":"Human 4-hydroxyphenylpyruvate dioxygenase / HPD","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"ea7ed42c-7c9f-5d5a-912a-7b67e60df93e","slug":"homogentisate","display_name":"Homogentisate","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":""},{"entity":{"id":"9e57c89c-2e87-5bc7-b2b9-29b122942fdd","slug":"4-hydroxyphenylpyruvate","display_name":"4-Hydroxyphenylpyruvate","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"89bcaf42-b4ab-5760-8c2e-44eace10cee0","slug":"iron","display_name":"Iron","entity_type_key":"nutrient_element"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"899c7ab0-6f81-5b38-a6bd-fbb33d66ac8d","slug":"oxygen","display_name":"Molecular oxygen","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human enzyme mutagenesis, binding assays and structural simulation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"HPD must not be merged with HPDL, which has a different product.","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":"The carbon skeleton passes through a separate oxygen-dependent enzyme.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Functional role of residues involved in substrate binding of human 4-hydroxyphenylpyruvate dioxygenase. · 2021 · https://pubmed.ncbi.nlm.nih.gov/34047349/ · DOI 10.1042/BCJ20210005","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"5840446d-b17a-5301-bec0-403a4c0d4ab5","evidence_kind":"source_excerpt","locator":"Lines 228-234","start_line":228,"end_line":234,"excerpt":"## l-tyrosine-hpd-hga\nThe carbon skeleton passes through a separate oxygen-dependent enzyme.\nHuman HPD converts 4-hydroxyphenylpyruvate to homogentisate; substrate-binding-site mutations altered catalytic efficiency.\nModel: Human enzyme mutagenesis, binding assays and structural simulation.\nLimitations: HPD must not be merged with HPDL, which has a different product.\nEvidence access: Primary abstract\nFunctional role of residues involved in substrate binding of human 4-hydroxyphenylpyruvate dioxygenase. · 2021 · https://pubmed.ncbi.nlm.nih.gov/34047349/ · DOI 10.1042/BCJ20210005","model_system":"Human enzyme mutagenesis, binding assays and structural simulation.","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}