This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'The thyroid hormone thyroxine (T4) is derived from? \nSelect and explain. \nA. Threonine, B. Tyrosine, C. Thiamine, D. Tryptophan', 'role': 'user'}, {'content': "Answer: B \nExplanation: 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),Harper's Illustrated Biochemistry, 29e.", 'role': 'assistant'}]