Enzyme deficient in maple syrup urine disease -

Ans. is 'a' i.e., alpha-ketoacid decarboxylase Maple syrup urine disease (MSUD) or branched chain ketoaciduriao It is an inborn error of metabolism of branched chain amino acids valine, leucine and isoleucineo It is due to deficiency of enzyme that catalyzes the second reaction in these amino acids metabolism i.e. branched chain-a keto acid dehydrogenase which catalyses decarboxylation of branched chain amino acids As a result, the branched chain amino acids, leucine, isoleucine and valine, and their a-keto acids accumulate in blood, urine and CSF.o There is characteristic maple syrup odor to the urine.