{"id":"bb01653e-496f-5b09-9c7e-032422738e08","stable_key":"63ce713e-6aea-59f6-9896-ca30e010b2ce:l-tyrosine-tg-iodinated-pairs","predicate":"provides","statement":"Human thyroglobulin cryo-EM and site-directed mutagenesis identified tyrosine donor-acceptor pairs supporting hormone formation in vitro.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"50650373-a6cf-5648-84d2-25d47f1e44b2","mechanism_event_label":"The thyroid uses selected tyrosines already built into a protein.","subject":{"id":"ab42f761-f2c0-52e6-876b-12df0d1d03d7","slug":"thyroglobulin","display_name":"Human thyroglobulin","entity_type_key":"protein"},"object":{"id":"7d332c8d-cb33-5dcc-bbfe-0629c4118f5d","slug":"human-tg-hormonogenic-tyrosine-pairs","display_name":"Human thyroglobulin hormonogenic tyrosine pairs","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"50650373-a6cf-5648-84d2-25d47f1e44b2","stable_key":"63ce713e-6aea-59f6-9896-ca30e010b2ce:l-tyrosine-tg-iodinated-pairs-event","event_type":"observed_relationship","label":"The thyroid uses selected tyrosines already built into a protein.","description":"Human thyroglobulin cryo-EM and site-directed mutagenesis identified tyrosine donor-acceptor pairs supporting hormone formation in vitro.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"ab42f761-f2c0-52e6-876b-12df0d1d03d7","slug":"thyroglobulin","display_name":"Human thyroglobulin","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"7d332c8d-cb33-5dcc-bbfe-0629c4118f5d","slug":"human-tg-hormonogenic-tyrosine-pairs","display_name":"Human thyroglobulin hormonogenic tyrosine pairs","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":""},{"entity":{"id":"83b11ca6-52c7-5a1b-8c39-d9cdf89244e3","slug":"iodide","display_name":"Iodide ion","entity_type_key":"ion"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"0516476b-cb34-5a25-ac87-db3657d29c92","slug":"protein-bound-tyrosine","display_name":"Protein-bound L-tyrosine residue","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"fd936be6-d715-5f97-a13e-3221b5edac60","slug":"tg-bound-monoiodotyrosyl-residues","display_name":"Thyroglobulin-bound monoiodotyrosyl residues","entity_type_key":"chemical_species"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""},{"entity":{"id":"ca877817-8e7f-5da4-b3c5-2a6345ddfae0","slug":"tg-bound-diiodotyrosyl-residues","display_name":"Thyroglobulin-bound diiodotyrosyl residues","entity_type_key":"chemical_species"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":6,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human TG expressed in HEK293T cells; cryo-EM and in vitro hormone assays.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This does not mean free tyrosine is directly iodinated into circulating thyroid hormone.","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 thyroid uses selected tyrosines already built into a protein.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"The structure of human thyroglobulin. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32025030/ · DOI 10.1038/s41586-020-1995-4","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"5e622aa3-1f41-560a-80ae-229201ba859e","evidence_kind":"source_excerpt","locator":"Lines 132-138","start_line":132,"end_line":138,"excerpt":"## l-tyrosine-tg-iodinated-pairs\nThe thyroid uses selected tyrosines already built into a protein.\nHuman thyroglobulin cryo-EM and site-directed mutagenesis identified tyrosine donor-acceptor pairs supporting hormone formation in vitro.\nModel: Human TG expressed in HEK293T cells; cryo-EM and in vitro hormone assays.\nLimitations: This does not mean free tyrosine is directly iodinated into circulating thyroid hormone.\nEvidence access: Primary abstract\nThe structure of human thyroglobulin. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32025030/ · DOI 10.1038/s41586-020-1995-4","model_system":"Human TG expressed in HEK293T cells; cryo-EM and in vitro hormone assays.","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. 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