<prompt> Thiamine deficiency causes lactic acidosis due to defect in the action of?Alpha - KG dehydrogenaseSorbitol reductaseLactate dehydrogenasePyruvate dehydrogenase  <response>: Ans. d Pyruvate dehydrogenase. Ref. Harper, Biochemistry, 25th ed., 197Inhibition of pyruvate metabolism leads to lactic acidosis. Arsenite, mercuric ions, dietary deficiency of thiamine, inhibits pyruvate dehydrogenase, and allows pyruvate to accumulate. Thiamine is a cofactor for several enzymes like- Transketolase,- Pyruvate dehydrogenase and- a-KG dehydrogenase. If nutritionally deprived alcoholics are given glucose, thiamine deficiency causes rapid accumulation of pyruvate and lactic acidosis. Patient with inherited pyruvate dehydrogenase deficiency have same features particularly after glucose load.IV thiamine is treatment of choice in Wernickes encephalopathy.QINHIBITORS OF METABOLIC PATHWAYS EnzymeInhibitorPathway1.AconitaseFluoroacetateKrebs cycle2.L-KG dehydrogenaseArseniteKrebs cycle3.EnolaseFluorideGlycolysis4.Succinate dehydrogenaseMalonate oxaloacetateKrebs cycle5,Giyceradehyde-3 phosphatelodoacetate dehydrogenaseGlycolysis6.MOAIproniazid 7.Pyruvate dehydrogenaseArsenite 8.Carbonic anhydraseSulfanilamide 