L-thyroxine (S)-2-amino-3-[4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl]propanoic acid 3',3'',5',5''-tetraiodo-L-thyronine 3,3',5,5'-tetraiodo-L-thyronine 3,5,3',5'-tetraiodo-L-thyronine 4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodo-L-phenylalanine 595.61279296875 595.67999267578125 758.6761474609375 758.8599853515625 A protein modification that effectively substitutes an L-tyrosine residue with L-thyroxine. C 15 H 9 I 4 N 1 O 3 C 6 H 0 I 4 N 0 O 1 I4Thy L-thyroxine MOD:00187 MOD_RES Thyroxine O-(4-hydroxy-3,5-diiodophenyl)-3,5-diiodo-L-tyrosine PSI-MOD T4 Thyroxine Unimod:398 Y natural tetraiodo uniprot.ptm:PTM-0294 iodinated tyrosine