3-iodotyrosine

**3-Iodotyrosine** is a halogenated derivative of the amino acid tyrosine, specifically iodinated at the meta (3-) position of the benzene ring. It serves as an intermediate in thyroid hormone biosynthesis, formed by iodination of tyrosine within the thyroid gland. In this pathway, one unit of 3-iodotyrosine can combine with diiodotyrosine to form triiodothyronine (T₃), and two units can combine to form 3,3'-diiodothyronine[2][10]. Beyond its physiological role in thyroid hormone synthesis, it is also a reversible inhibitor of tyrosine hydroxylase—the rate-limiting enzyme in catecholamine (dopamine) biosynthesis—making it useful for research into dopamine pathways and neurodegenerative diseases[2][10]. It is not approved as a pharmaceutical drug but is widely used experimentally for biochemical assays and metabolic studies.

Other names

3-Iodo-L-tyrosineL-Tyrosine, 3-iodo-Monoiodotyrosine3-IODOTYROSINEH-Tyr(3-I)-OHH-L-TYR(3-I)-OH