Iodination and coupling of the hormonogenic tyrosines in thyroglobulin to yield the thyroid hormones T(3) and T(4). 2 H(+) + H2O2 + 2 iodide = diiodine + 2 H2O [thyroglobulin]-L-tyrosine + H(+) + H2O2 + iodide = [thyroglobulin]-3-iodo-L-tyrosine + 2 H2O [thyroglobulin]-3-iodo-L-tyrosine + H(+) + H2O2 + iodide = [thyroglobulin]-3,5-diiodo-L-tyrosine + 2 H2O 2 [thyroglobulin]-3,5-diiodo-L-tyrosine + H2O2 = [thyroglobulin]-dehydroalanine + [thyroglobulin]-L-thyroxine + 2 H2O [thyroglobulin]-3,5-diiodo-L-tyrosine + [thyroglobulin]-3-iodo-L-tyrosine + H2O2 = [thyroglobulin]-3,3',5-triiodo-L-thyronine + [thyroglobulin]-dehydroalanine + 2 H2O Binds 1 Ca(2+) ion per heterodimer. Binds 1 heme b (iron(II)-protoporphyrin IX) group covalently per heterodimer. Hormone biosynthesis; thyroid hormone biosynthesis. Interacts with DUOX1, DUOX2 and CYBA. Additional isoforms seem to exist. Glycosylated. Heme is covalently bound through a H(2)O(2)-dependent autocatalytic process. Heme insertion is important for the delivery of protein at the cell surface. Cleaved in its N-terminal part. An alternative splicing in the thyroperoxidase mRNA can cause Graves' disease. The disease is caused by variants affecting the gene represented in this entry. Lacks exon 10. Found in normal thyroid tissues as well as Graves'tissues. Rapidly degraded after synthesis, does not reach the cell surface. Inactive. Lacks exon 16. Found in normal thyroid tissues as well as Graves'tissues. Active. Lacks exon 14. Active. Lacks exon 8. Does not fold correctly. Does not reach the cell surface. Lacks exons 10, 12, 13, 14 and 16. Lacks exons 10 and 16. Lacks exons 10 and 14. Belongs to the peroxidase family. XPO subfamily. Thyroid peroxidase entry