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: Biochemistry
[{'content': 'Biotin is required for the activity of \nSelect and explain. \nA. Pyruvate carboxylase, B. Lactate dehydrogenase, C. Succinate thiokinase, D. Phosphohexose isomerase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Mitochondrial pyruvate carboxylase catalyzes the carboxylation of pyruvate to oxaloacetate, an ATP-\xa0 requiring reaction in which the vitamin biotin is the coenzyme.\nBiotin binds CO2 from bicarbonate as carboxybiotin prior to the addition of the CO2 to pyruvate.\nThe resultant oxaloacetate is reduced to malate, exported from the mitochondrion into the cytosol\xa0 and there oxidized back to oxaloacetate.\n\nKey Concept:\nBiotin is the co-enzyme for pyruvate carboxylase which carboxylates pyruvate into oxaloacetate\nRef : Harper’s illustrated biochemistry, 31st edition.', 'role': 'assistant'}]