This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
Creatinine is formed from all except - 
Select and explain. 
A. Glycine, B. Arginine, C. Methionine, D. Asparagine
D: Asparagine
Answer: D: Asparagine 
Explanation: Ans. is 'd' i.e., Asparagine * The three aminoacids used for the synthesis of creatine are Glycine, Arginine and Methionine* In Kidney, Glycine reacts with Arginine in the presence of Arginine Glycine Amido Transferase to for Guanidoacetate and Ornithine* Guanidoacetate through circulation is taken to liver. In liver Guanidoacetate undergoes transmethylation reaction with S- Adenosyl Methionine in the presence of Guanidoacetate Methyl Transferase to form Creatine.* The creatine through circulation reaches tissues.* 90% of creatine is taken up by skeletal muscles and is phosphorylated by creatine Kinase to form creatine Phosphate.* This creatine phosphate acts as the immediate source of energy for skeletal muscle.