Purification is the same as for the D-isomer above. Likely impurities are tyrosine, iodotyrosine, iodothyroxines and iodide. Dissolve it in dilute ammonia at room temperature, then crystallise it by adding di 546 +27.8o (c 5, EtOH). [Harrington et al. Biochem J 39 164 1945, Nahm & Siedel Chem Ber 96 1 1963, Reineke & Turner J Biol Chem 161 613 1945, Chalmers et al. J Chem Soc 3424 1949, Beilstein 14 II 378, 14 III 1566, 14 IV 2373.]
ChEBI: The L-enantiomer of thyroxine.
Levolet (Vintage); Levothroid (Lloyd); Levoxyl (Jones);
Novothyrox (Genpharm); Synthroid (Abbott); Unithroid
One of the thyroid hormones involved in the maintenance of metabolic homeostasis. Synthesized and stored as amino acid residues of thyroglobulin, the major protein component of the thyroid follicular
colloid. Synthesis and secretion are regulated by the pituitary hormone (TSH). Deiodinated in peripheral tissues to the active metabolite, liothyronine. The D-form has very little activity as a thyroi
d hormone, but has been used to treat hyperlipidemia.