{"id":"d066704a-441b-55d0-87ee-f167cd384bbc","stable_key":"aaa7baba-8689-56ab-ba1e-b71542bcb8e9:iodine-syn-tpo-t3-formation","predicate":"catalyzes","statement":"Iodinating human goiter TG with hog TPO for 90 minutes produced 0.3 T3 residues per TG molecule, measured after enzymatic hydrolysis.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"b710d099-fc0a-5e8c-8a3c-80c2775bb679","mechanism_event_label":"TPO-driven chemistry can make T3 directly within TG, before the hormone is released.","subject":{"id":"a524c063-3d56-5ec2-95c1-6bb74b14af82","slug":"porcine-tpo","display_name":"Porcine thyroid peroxidase","entity_type_key":"protein"},"object":{"id":"6ef929b8-7242-5690-a379-597a043b6a0e","slug":"human-thyroglobulin-t3-bearing","display_name":"Human thyroglobulin containing covalent T3 residues","entity_type_key":"protein_state"},"evidence_count":1,"mechanism_event":{"id":"b710d099-fc0a-5e8c-8a3c-80c2775bb679","stable_key":"aaa7baba-8689-56ab-ba1e-b71542bcb8e9:iodine-syn-tpo-t3-formation-event","event_type":"biochemical_relationship","label":"TPO-driven chemistry can make T3 directly within TG, before the hormone is released.","description":"Iodinating human goiter TG with hog TPO for 90 minutes produced 0.3 T3 residues per TG molecule, measured after enzymatic hydrolysis.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"ab42f761-f2c0-52e6-876b-12df0d1d03d7","slug":"thyroglobulin","display_name":"Human thyroglobulin","entity_type_key":"protein"},"role":"human_protein_substrate","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"83b11ca6-52c7-5a1b-8c39-d9cdf89244e3","slug":"iodide","display_name":"Iodide ion","entity_type_key":"ion"},"role":"iodine_source","stoichiometry":null,"state_label":"","sequence_order":1,"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":"TG_iodotyrosyl_pool","stoichiometry":null,"state_label":"","sequence_order":2,"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":"TG_iodotyrosyl_pool","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"559f37d2-ee0a-589b-8689-fa80ca9ae653","slug":"triiodothyronine","display_name":"T3","entity_type_key":"small_molecule"},"role":"product_measured_after_hydrolysis","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"a524c063-3d56-5ec2-95c1-6bb74b14af82","slug":"porcine-tpo","display_name":"Porcine thyroid peroxidase","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""},{"entity":{"id":"6ef929b8-7242-5690-a379-597a043b6a0e","slug":"human-thyroglobulin-t3-bearing","display_name":"Human thyroglobulin containing covalent T3 residues","entity_type_key":"protein_state"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":6,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"false","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/iodine-synthesis-sources/7372636.txt\", \"start_char\": 6216, \"end_char\": 8536, \"text_sha256\": \"753e684061b9063528196c840b23404015abc2b7b836a3887497aea0f8fe20a6\", \"text_characters\": 2320, \"note\": \"Exact publisher passage retained in the cited local source cache; locator and digest supplied here.\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified hog TPO with human goiter TG or tyrosine-radiolabeled hog TG; chromatographic hormone and dehydroalanine analyses","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Human goiter TG initially 0.04% iodine, iodinated for 90 minutes to approximately 60 iodine atoms per TG; the same preparation contained 2.6 T4 residues per molecule.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Reconstituted mixed-species experiment. Hormone residues are protein-bound before hydrolysis; the assay is not evidence that free MIT and DIT are routinely coupled in blood.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Iodine research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"iodine","display_name":"Iodine","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Sus scrofa enzyme; Homo sapiens substrate","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"TPO-driven chemistry can make T3 directly within TG, before the hormone is released.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[iodine-syn-tpo-coupling1980] Formation of dehydroalanine residues during thyroid hormone synthesis in thyroglobulin. (1980). https://pubmed.ncbi.nlm.nih.gov/7372636/ DOI: 10.1016/S0021-9258(19)70782-0","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified TPO and human goiter TG","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c9781321-4842-5c1d-8f27-ca110e956c9f","evidence_kind":"source_excerpt","locator":"Lines 856-868","start_line":856,"end_line":868,"excerpt":"### iodine-syn-tpo-t3-formation\nIodinating human goiter TG with hog TPO for 90 minutes produced 0.3 T3 residues per TG molecule, measured after enzymatic hydrolysis.\nCondition category: normal\nnutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: TPO-driven chemistry can make T3 directly within TG, before the hormone is released.\norganism: Sus scrofa enzyme; Homo sapiens substrate\ntissue_or_cell_type: Purified TPO and human goiter TG\nexperimental_model: Purified hog TPO with human goiter TG or tyrosine-radiolabeled hog TG; chromatographic hormone and dehydroalanine analyses\nlimitations: Reconstituted mixed-species experiment. Hormone residues are protein-bound before hydrolysis; the assay is not evidence that free MIT and DIT are routinely coupled in blood.\nexposure: Human goiter TG initially 0.04% iodine, iodinated for 90 minutes to approximately 60 iodine atoms per TG; the same preparation contained 2.6 T4 residues per molecule.\ncross_nutrient: false\nevidence_span: {\"source_cache\": \"artifacts/iodine-synthesis-sources/7372636.txt\", \"start_char\": 6216, \"end_char\": 8536, \"text_sha256\": \"753e684061b9063528196c840b23404015abc2b7b836a3887497aea0f8fe20a6\", \"text_characters\": 2320, \"note\": \"Exact publisher passage retained in the cited local source cache; locator and digest supplied here.\"}\n[iodine-syn-tpo-coupling1980] Formation of dehydroalanine residues during thyroid hormone synthesis in thyroglobulin. (1980). https://pubmed.ncbi.nlm.nih.gov/7372636/ DOI: 10.1016/S0021-9258(19)70782-0","model_system":"Purified hog TPO with human goiter TG or tyrosine-radiolabeled hog TG; chromatographic hormone and dehydroalanine analyses","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [iodine-syn-tpo-coupling1980] Formation of dehydroalanine residues during thyroid hormone synthesis in thyroglobulin. (1980). https://pubmed.ncbi.nlm.nih.gov/7372636/ DOI: 10.1016/S0021-9258(19)70782-0","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"76da623d-a34a-5a5c-a942-d7571a85c486","stable_key":"import-aaa7baba-8689-56ab-ba1e-b71542bcb8e9","title":"Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"a4885eb6f58bad4a4514c958b63834619e57b10aa7f694aa97d0f65c7d36548f","revision_id":"ea8001a1-b576-5eda-a193-883c7ad59b73","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}