What is the primary enzyme responsible for the breakdown of branched-chain amino acids, and its deficiency leads to a condition characterized by urine that smells like maple syrup?

A Branched-chain alpha-keto acid dehydrogenase ✓
B Phenylalanine hydroxylase
C Tyrosinase
D Homogentisate 1,2-dioxygenase

Explanation

The primary enzyme responsible for the breakdown of branched-chain amino acids is branched-chain alpha-keto acid dehydrogenase. A deficiency in this enzyme leads to maple syrup urine disease, a condition characterized by urine that smells like maple syrup.

Mnemonic

BCAA = Branched-Chain Amino Acids, BCKAD = Breaks Chain

Source

NCERT Class 12 Biochemistry
Enzymes in Disease Biochemistry Amino Acid Metabolism Disorders Medium MEDICAL Confidence: high