Thiamine pyrophosphate (TPP), the active coenzyme form of vitamin B1, serves as a cofactor for which of the following enzymatic reactions?
- A Conversion of pyruvate to acetyl-CoA only
- B Decarboxylation of pyruvate to acetyl-CoA and alpha-ketoglutarate to succinyl-CoA ✓
- C Conversion of homocysteine to methionine
- D Hydroxylation of dopamine to noradrenaline
Correct answer: B. Decarboxylation of pyruvate to acetyl-CoA and alpha-ketoglutarate to succinyl-CoA
Explanation
TPP is a cofactor for pyruvate dehydrogenase (pyruvate to acetyl-CoA), alpha-ketoglutarate dehydrogenase (alpha-ketoglutarate to succinyl-CoA) in the TCA cycle, and transketolase in the pentose phosphate pathway. In thiamine deficiency, pyruvate is shunted to lactate. Option A is incomplete because it omits the TCA cycle reaction, making it a strong partial-knowledge distractor.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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