Biochemistry General 23a248cb Which of the following is the precursor of adrenaline and noradrenaline? A Phenylalanine B Tyrosine C Tryptophan D None of the above High-Yield Explanation Tyrosine is the contributing amino acid for the formation of thyroxine, tri-iodothyronine, epinephrine, norepinephrine, dopamine and melanin