Which set of cofactors is required by the alpha-ketoglutarate dehydrogenase complex?
- A Thiamine pyrophosphate, lipoic acid, CoA, FAD, NAD+ ✓
- B Pyridoxal phosphate, biotin, CoA, FAD, NAD+
- C Thiamine pyrophosphate, biotin, CoA, NAD+, vitamin B12
- D Lipoic acid, folate, CoA, FAD, NADP+
Correct answer: A. Thiamine pyrophosphate, lipoic acid, CoA, FAD, NAD+
Explanation
Alpha-ketoglutarate dehydrogenase is a multienzyme complex mechanistically identical to pyruvate dehydrogenase, requiring the same five cofactors: TPP, lipoamide, CoA, FAD, and NAD+. Biotin is the cofactor of carboxylases such as pyruvate carboxylase, and pyridoxal phosphate belongs to transaminases, so options B and C are killed by their inclusion of the wrong vitamins.
Reference: Lippincott's Illustrated Reviews: Biochemistry, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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