Diiodotyrosine (DIT) is an iodinated derivative of the amino acid tyrosine. It is a crucial intermediate in the biosynthesis of thyroid hormones. In the thyroid gland, tyrosine residues within the protein thyroglobulin are iodinated to form either monoiodotyrosine (MIT) or diiodotyrosine (DIT). The coupling of one MIT and one DIT forms triiodothyronine (T3), while the coupling of two DIT molecules forms thyroxine (T4).
