Reaction: (1) 2 iodide + H2O2 + 2 H+ = diiodine + 2 H2O
(2) [thyroglobulin]-L-tyrosine + iodide + H2O2 = [thyroglobulin]-3-iodo-L-tyrosine + 2 H2O
(3) [thyroglobulin]-3-iodo-L-tyrosine + iodide + H2O2 = [thyroglobulin]-3,5-diiodo-L-tyrosine + 2 H2O
(4) 2 [thyroglobulin]-3,5-diiodo-L-tyrosine + H2O2 = [thyroglobulin]-L-thyroxine + [thyroglobulin]-aminoacrylate + 2 H2O
(5) [thyroglobulin]-3-iodo-L-tyrosine + [thyroglobulin]-3,5-diiodo-L-tyrosine + H2O2 = [thyroglobulin]-3,5,3'-triiodo-L-thyronine + [thyroglobulin]-aminoacrylate + 2 H2O
Glossary: 3,5,3'-triiodo-L-thyronine = triiodo-L-thyronine
Other name(s): thyroid peroxidase; iodoperoxidase (heme type); iodide peroxidase-tyrosine iodinase; thyroperoxidase; tyrosine iodinase; TPO; iodinase
Systematic name: iodide:hydrogen-peroxide oxidoreductase
Comments: Thyroid peroxidase catalyses the biosynthesis of the thyroid hormones L-thyroxine and triiodo-L-thyronine. It catalyses both the iodination of tyrosine residues in thyroglobulin (forming mono- and di-iodinated forms) and their coupling to form either L-thyroxine or triiodo-L-thyronine.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9031-28-1
References:
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