This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: vitamins, Subject name: Biochemistry
[{'content': 'The role of vitamin K in epoxide cycle is \nSelect and explain. \nA. Carboxylation of glucatamate, B. Dehydrogenation of glucatamate, C. Carboxylation of glutamate, D. Dehydrogenation of aspaate', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Carboxylation of glutamate is the role of VitK in epoxide cycle. Vitamin K is necessary for coagulation. Factors dependent on vitamin K are Factor II (prothrombin); Factor VII (SPCA); Factor IX (Christmas factor); Factor X (Stua Prower factor) All these factors are synthesized by the liver as inactive zymogens. They undergo post-translational modification; gamma-carboxylation of glutamic acid residues. These are the binding sites for calcium ions. The gamma-carboxy glutamic acid (GCG) synthesis requires vitamin K as a co-factor Ref: DM Vasudevan - Textbook of Biochemistry, 8th edition, page no: 462 image satyanarayana 4th ed page 131', 'role': 'assistant'}]