This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Gamma - Carboxylation of what requires vitamin k? \nSelect and explain. \nA. Glutamine, B. Glutamic Acid, C. Glycine, D. Aspartate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Vitamin K\nFunction\n1.\xa0\xa0 Catalyzes gamma-carboxylation of glutamic acid residues on various proteins concerned with blood clotting.\n2.\xa0\xa0 Catalyzes gamma carboxylaton of glutamic acid to GABA.\nDeficiency\n1.\xa0\xa0 Neonatal haemorrhage with increased PT and aPTT, but normal bleeding time.\n2.\xa0\xa0 Synthesized by intestinal flora, so vitamin-K deficiency can occur after the prelonged use of broad-spectrum antibiotics.\n\xa0\xa0\xa0\xa0\xa0 (Note: Vitamin-K dependent clotting factors are II, VII, IX, X and protein C and S. Warfarin is a vitamin-K antagonist)\n\xa0\xa0\xa0\xa0\xa0 A specific protein known as PIVKA (Protein induced in vitamin K absence) is important in diagnosing vitamin K deficiency.', 'role': 'assistant'}]