Which enzyme's deficiency leads to maple syrup urine disease, characterized by the accumulation of branched-chain amino acids?

A Phenylalanine hydroxylase
B Branched-chain alpha-keto acid dehydrogenase complex ✓
C Tyrosinase
D Glutathione synthetase

Explanation

The branched-chain alpha-keto acid dehydrogenase complex is necessary for the breakdown of branched-chain amino acids; its deficiency results in their accumulation and leads to maple syrup urine disease.

Source

NCBI: Maple Syrup Urine Disease
Enzymes in Disease Metabolic Disorders Amino Acid Metabolism Disorders Hard MEDICAL Confidence: high