<prompt> The thyroid hormone thyroxine T4 is derived from?ThreonineTyrosineThiamineTryptophan  <response>: Thyroxine is a derivative of tyrosine. It is formed by the iodination and joining of peptide-linked tyrosyl residues of thyroglobulin. Proteolysis of thyroglobulin yields thyroxine. Thyroxine is also called tetraiodothyronine, or T4, because of the four iodine atoms of the thyroid hormone. Ref:Weil P. 2011. Chapter 41. The Diversity of the Endocrine System. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell Eds,Harpers Illustrated Biochemistry, 29e. 