Which of the following is the precursor of adrenaline and noradrenaline?: (A) Phenylalanine, (B) Tyrosine, (C) Tryptophan, (D) None of the above
Answer is B. Tyrosine is the contributing amino acid for the formation of thyroxine, tri-iodothyronine, epinephrine, norepinephrine, dopamine and melanin