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
Glutamine synthetase is a 
Select and explain. 
A. Isomerase, B. Ligase, C. Lyase, D. Transferase
B: Ligase
Answer: B: Ligase 
Explanation: Ligases are enzymes that link two substrate together,usually with the simultaneous hydrolysis of ATP. Glutamine synthetase catalyses the amidation of glutamic acid to glutamine.Ref: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 49 and 224