Human Metabolome Database: Iodotyrosine
An iodated derivative of L-tyrosine. This is an early precursor to L-thyroxine, one of the primary thyroid hormones. In the thyroid gland, iodide is trapped, transported, and concentrated in the follicular lumen for thyroid hormone synthesis. Before trapped iodide can react with tyrosine residues, it must be oxidized by thyroid peroxidase. Iodotyrosine is made from tyrosine via thyroid peroxidase and then further iodinated by this enzyme to make the di-iodo an tri-iodo variants. Two molecules of di-iodotyrosine combine to form T4, and one molecule of mono-iodotyrosine combines with one molecule of di-iodotyrosine to form T3.