Synthesis of one molecule of palmitate requires 14 NADPH. In human adipose tissue, an important source of this NADPH is the enzyme that oxidatively decarboxylates malate to pyruvate while reducing NADP+. This enzyme is:
- A Malate dehydrogenase (mitochondrial)
- B Malic enzyme (NADP+-dependent) ✓
- C Isocitrate dehydrogenase (NADP+-dependent)
- D Glucose-6-phosphate dehydrogenase
Correct answer: B. Malic enzyme (NADP+-dependent)
Explanation
Cytosolic NADP+-dependent malic enzyme converts malate (generated when oxaloacetate from the citrate shuttle is reduced) to pyruvate, producing NADPH for lipogenesis. Glucose-6-phosphate dehydrogenase is the major hepatic NADPH source but the question specifies the malate-to-pyruvate reaction. Mitochondrial malate dehydrogenase uses NAD+ and serves the shuttle, not NADPH generation.
Reference: Lehninger Principles of Biochemistry, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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