This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Carbohydrates, Subject name: Biochemistry
Lactic acidosis in thiamine deficiency is due to which enzyme dysfunction? 
Select and explain. 
A. Phosphoenol pyruvate carboxykinase, B. Pyruvate dehydrogenase, C. Pyruvate carboxylase, D. Aldolase
B: Pyruvate dehydrogenase
Answer: B: Pyruvate dehydrogenase 
Explanation: Ans. B. Pyruvate dehydrogenase(Ref: Harper 31/e page 138)In Thiamine deficiency, PDH reaction is defective. So Pyruvate is converted to lactic acid.Causes of inhibition PDH leading to lactic acidosisInherited PDH deficiency.Thiamin deficiency.Alcoholics due to thiamine deficiency.Arsenite and Mercury poisoning.