{"id":"e8aa2ad6-b93c-5081-81cd-7fb74c105b43","stable_key":"aaa7baba-8689-56ab-ba1e-b71542bcb8e9:iodine-syn-coupling-dehydroalanine","predicate":"generates_during_coupling","statement":"During TPO-catalyzed hormone formation in TG, approximately one protein-bound dehydroalanine residue was formed per hormone residue.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"3ee98729-4875-5e60-b3eb-7ca72bd8b25a","mechanism_event_label":"Coupling leaves a dehydroalanine remnant on the donor side of TG while creating a hormone residue.","subject":{"id":"a524c063-3d56-5ec2-95c1-6bb74b14af82","slug":"porcine-tpo","display_name":"Porcine thyroid peroxidase","entity_type_key":"protein"},"object":{"id":"de74a4d4-be3f-5a16-9f0e-25a36a7141d9","slug":"tg-bound-dehydroalanyl-residues","display_name":"Thyroglobulin-bound dehydroalanyl residues","entity_type_key":"chemical_species"},"evidence_count":1,"mechanism_event":{"id":"3ee98729-4875-5e60-b3eb-7ca72bd8b25a","stable_key":"aaa7baba-8689-56ab-ba1e-b71542bcb8e9:iodine-syn-coupling-dehydroalanine-event","event_type":"biochemical_relationship","label":"Coupling leaves a dehydroalanine remnant on the donor side of TG while creating a hormone residue.","description":"During TPO-catalyzed hormone formation in TG, approximately one protein-bound dehydroalanine residue was formed per hormone residue.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"ab42f761-f2c0-52e6-876b-12df0d1d03d7","slug":"thyroglobulin","display_name":"Human thyroglobulin","entity_type_key":"protein"},"role":"human_substrate_arm","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"74b9436f-3eb4-5e91-8981-f72f13c0feba","slug":"porcine-thyroglobulin","display_name":"Porcine thyroglobulin","entity_type_key":"protein"},"role":"porcine_substrate_arm","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":"iodinated_residue_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":"iodinated_residue_pool","stoichiometry":null,"state_label":"","sequence_order":3,"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":4,"notes":""},{"entity":{"id":"de74a4d4-be3f-5a16-9f0e-25a36a7141d9","slug":"tg-bound-dehydroalanyl-residues","display_name":"Thyroglobulin-bound dehydroalanyl residues","entity_type_key":"chemical_species"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":5,"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\": 1081, \"end_char\": 2101, \"text_sha256\": \"5ea5287db6f28391150ad5b783a0be5e450fd71f22b92028fefb7900c686c636\", \"text_characters\": 1020, \"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":"Hog TPO with human goiter TG and radiolabeled hog TG; dehydroalanine quantified after benzyl-mercaptan addition or borohydride reduction and hydrolysis.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Chemical trapping identifies the retained donor remnant; it does not prove every proposed radical intermediate or identify individual T3 donor sites.","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 and Sus scrofa TG in separate experiments","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Coupling leaves a dehydroalanine remnant on the donor side of TG while creating a hormone residue.","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-protein reactions","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c053300a-7d6d-5305-b13a-7bc15f2a895d","evidence_kind":"source_excerpt","locator":"Lines 870-882","start_line":870,"end_line":882,"excerpt":"### iodine-syn-coupling-dehydroalanine\nDuring TPO-catalyzed hormone formation in TG, approximately one protein-bound dehydroalanine residue was formed per hormone residue.\nCondition category: normal\nnutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Coupling leaves a dehydroalanine remnant on the donor side of TG while creating a hormone residue.\norganism: Sus scrofa enzyme; Homo sapiens and Sus scrofa TG in separate experiments\ntissue_or_cell_type: Purified-protein reactions\nexperimental_model: Purified hog TPO with human goiter TG or tyrosine-radiolabeled hog TG; chromatographic hormone and dehydroalanine analyses\nlimitations: Chemical trapping identifies the retained donor remnant; it does not prove every proposed radical intermediate or identify individual T3 donor sites.\nexposure: Hog TPO with human goiter TG and radiolabeled hog TG; dehydroalanine quantified after benzyl-mercaptan addition or borohydride reduction and hydrolysis.\ncross_nutrient: false\nevidence_span: {\"source_cache\": \"artifacts/iodine-synthesis-sources/7372636.txt\", \"start_char\": 1081, \"end_char\": 2101, \"text_sha256\": \"5ea5287db6f28391150ad5b783a0be5e450fd71f22b92028fefb7900c686c636\", \"text_characters\": 1020, \"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}