This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
Glycine is used in the synthesis of 
Select and explain. 
A. Nitric oxide, B. Catecholamines, C. Melanin, D. Purines
D: Purines
Answer: D: Purines 
Explanation: The whole of glycine is incorporated into the purine ring. (C4, C5, and N7)Ref: DM Vasudevan - Textbook of Biochemistry for Medical Students, 7th edition, page no: 212