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: Pharmacology
[{'content': "Large dose of EDTA are used in carbonic anhydrase enzyme inactivation. The mechanism by which EDTA act is - \nSelect and explain. \nA. It chelates with the metal ions of the enzyme, B. It combines with the substrate and reacts with the enzyme, C. Combines with the substrate and doesn't react with the enzyme, D. Enzyme-EDTA complex can not be attached to substrate", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., It chelates with metal ions of the enzyme o EDTA is a chelating agent and it has already been explained that chelating agent has legands (reactive groups) for metal binding. o These ligands of chelating agent bind to metal ions and cause chelation. o EDTA binds to zinc ion of carbonic anhydrase and this results in formation of ternary complex involving the enzyme, chelating agent and metal ions. The formation of ternary complex results in inactivation of enzyme.", 'role': 'assistant'}]