Which amino acid undergoes iodination during the biosynthesis of thyroid hormones?

Tyrosine is the amino acid that undergoes iodination during the biosynthesis of thyroid hormones, specifically thyroxine (T4) and triiodothyronine (T3). In the thyroid gland, tyrosine residues in the protein thyroglobulin are modified through the addition of iodine atoms. This process is catalyzed by the enzyme thyroperoxidase, and it involves the formation of monoiodotyrosine (MIT) and diiodotyrosine (DIT). Subsequently, these iodinated tyrosine residues undergo further coupling reactions to form the active thyroid hormones.

The significance of this process lies in the role of thyroid hormones in regulating metabolism, growth, and development. The availability of iodine is crucial for the synthesis of these hormones, emphasizing the importance of nutrition in thyroid health. The correct identification of tyrosine as the amino acid involved in this iodination process reflects its unique function and significance in thyroid hormone production.