iodide peroxidase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: iodide + H2O2 = iodine + 2 H2O. [RHEA:23336]

Iodide peroxidase activity is a crucial enzymatic process involved in the biosynthesis of thyroid hormones, which are essential for normal growth, development, and metabolism. The enzyme catalyzes the oxidation of iodide ions (I-) to iodine (I2) using hydrogen peroxide (H2O2) as the oxidant. This reaction occurs within the thyroid follicular cells, specifically in the lumen of the thyroid follicles.

The iodide peroxidase enzyme is a heme-containing enzyme, meaning it possesses a heme prosthetic group. This heme group is essential for the catalytic activity of the enzyme. During the catalytic cycle, iodide ions bind to the enzyme's active site, where they are oxidized by the heme group. The resulting iodine molecules then react with tyrosine residues on thyroglobulin, a large protein that serves as a precursor for thyroid hormones.

The iodination of thyroglobulin is a critical step in thyroid hormone synthesis. The iodine atoms are incorporated into specific tyrosine residues on the thyroglobulin molecule, forming monoiodotyrosine (MIT) and diiodotyrosine (DIT). These iodinated tyrosine residues can then undergo coupling reactions to form the active thyroid hormones thyroxine (T4) and triiodothyronine (T3).

Overall, iodide peroxidase activity is a vital process for the production of thyroid hormones. The enzyme's ability to oxidize iodide ions and facilitate the iodination of thyroglobulin is essential for the synthesis of T4 and T3, which regulate a wide range of physiological functions in the body.'
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Proteins (1)

Compounds (3)