All of the following are derivatives of tryptophan EXCEPT:: (A) Melatonin, (B) Serotonin, (C) Niacin, (D) Creatinine
Answer is D. Ans. (d) Creatinine* Tryptophan is one of the essential aromatic amino acid* Metabolic fate of tryptophan: Metabolized by enzyme Tryptophan oxygenase (pyrrolase)* Derivatives of tryptophan:# Niacin (Nicotinic acid)# Serotonin# Melatonin* Note: Creatinine is synthesized from 3 amino acids namely: Glycine, Arginine. Methionine