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
Enzyme defective in Maple syrup urine disease is: 
Select and explain. 
A. Tyrosinase, B. Phenylalanine hydroxylase, C. Branched chain alpha ketoacid dehydrogenase, D. Homogentisate oxidase
C: Branched chain alpha ketoacid dehydrogenase
Answer: C: Branched chain alpha ketoacid dehydrogenase 
Explanation: Enzyme deficiencies and conditionsTyrosinase is deficient in albinismPhenylalanine hydroxylase is deficient in phenylketonuriaMaple syrup urine disease is due to a defect in the enzyme branched chain alpha-keto acid dehydrogenaseHomogentisate oxidase is deficient in alkaptonuria