Question:medium
Which of the following is not the source of cytosolic NADPH ?
Which of the following is not the source of cytosolic NADPH ?
Updated On: Jun 23, 2026
- Isocitrate dehydrogenase
- ATP citrate lyase
- Malic enzyme
- G6PD
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: List the cytosolic reactions that yield NADPH and find the odd one out.
Step 2: The pentose phosphate pathway via G6PD is the dominant supplier, and cytosolic NADP-dependent isocitrate dehydrogenase plus malic enzyme add more NADPH.
Step 3: ATP citrate lyase has a different job: it uses ATP to split citrate exported from mitochondria into acetyl-CoA (the building block for lipid synthesis) and oxaloacetate.
Step 4: Because ATP citrate lyase produces acetyl-CoA rather than NADPH, it is the enzyme that is not a NADPH source. \[\boxed{\text{ATP citrate lyase}}\]
Step 2: The pentose phosphate pathway via G6PD is the dominant supplier, and cytosolic NADP-dependent isocitrate dehydrogenase plus malic enzyme add more NADPH.
Step 3: ATP citrate lyase has a different job: it uses ATP to split citrate exported from mitochondria into acetyl-CoA (the building block for lipid synthesis) and oxaloacetate.
Step 4: Because ATP citrate lyase produces acetyl-CoA rather than NADPH, it is the enzyme that is not a NADPH source. \[\boxed{\text{ATP citrate lyase}}\]
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