Which enzyme is responsible for the degradation of branched-chain amino acids in maple syrup urine disease?

A Branched-chain alpha-keto acid dehydrogenase ✓
B Branched-chain aminotransferase
C Isovaleryl-CoA dehydrogenase
D Methylmalonyl-CoA mutase

Explanation

Branched-chain alpha-keto acid dehydrogenase is the enzyme responsible for the degradation of branched-chain amino acids, and its deficiency leads to maple syrup urine disease.

Source

Scriver's The Metabolic and Molecular Bases of Inherited Disease
Enzymes in Disease Biochemistry Amino Acid Metabolism Hard MEDICAL Confidence: high