Biotin serves as a cofactor for carboxylase enzymes. A patient with raw egg consumption-induced biotin deficiency will primarily show impaired activity of which set of enzymes?
- A Acetyl-CoA carboxylase, pyruvate carboxylase, propionyl-CoA carboxylase, 3-methylcrotonyl-CoA carboxylase ✓
- B Transketolase, pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase
- C Glutamate dehydrogenase, alanine aminotransferase, aspartate aminotransferase
- D Homocysteine methyltransferase, methionine synthase, methylmalonyl-CoA mutase
Explanation
Biotin is a covalently bound cofactor for four mitochondrial carboxylases: acetyl-CoA carboxylase (fatty acid synthesis), pyruvate carboxylase (gluconeogenesis and anaplerosis), propionyl-CoA carboxylase (odd-chain fatty acid and branched-chain amino acid catabolism), and 3-methylcrotonyl-CoA carboxylase (leucine catabolism). Avidin in raw egg white binds biotin with extremely high affinity, preventing intestinal absorption. Biotinidase deficiency (an inborn error) causes similar multi-carboxylase deficiency. TPP-dependent enzymes (transketolase, pyruvate dehydrogenase) are affected by thiamine deficiency.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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