NH CH -CH-COOH L-tyrosine CH.-CH-COOH HO >CH2-CH-COOH monoiodo tyrosine(MIT) diiodotyrosine(DIT) NH 2 HO CH2-CH-COOH 3, 5. 3'-triodothyronine (T3) NH CH2-CH-COOH 3, 5, 3, 5, tetraiodothyronine(Ta) thyroxine)