<prompt> Serotonin is:5 Hydroxy tryptophan5 Hydroxy tryptamine5 Carboxy tryptamine5 Carboxy tryptophan  <response>: Ans. B. 5 Hydroxytryptamine5 Hydroxy Tryptophan is decarboxylated by Aromatic aminoacid decarboxylase to form 5 Hydroxytryptamine or Serotonin. Coenzyme is PLP. 