<prompt> Which one of the following combination is wrong?Phenylalanine - NiacinTrytophon - SerotoninPhenylalanine - MelaninTyrosine - Epinephrine  <response>: Niacin is formed by metabolism of tryptophan. Other options are correct amino acids and their metabolic productsRef: Textbook of biochemistry for medical students, seventh edition, page no: 239 