This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tryptophan metabolism detail, Subject name: Biochemistry
Xanthoproteic test is used for - 
Select and explain. 
A. Ketone bodies, B. Bile salts, C. Amino acids, D. Reducing sugars
C: Amino acids
Answer: C: Amino acids 
Explanation: Xanthoproteic test is a color (yellow) reaction of proteins This test is Positive for aromatic amino acids only. Note: Xanthurenic acid is the metabolite in the metabolism of tryptophan.