Question

How many ATP equivalents are produced by the oxidation of succinate into fumarate?

• A. 1 ATP
• B. 2 ATP
• C. 3 ATP
• D. 4 ATP

Answer 1

Answer: (B)

2 ATP

• Oxidation of succinate to fumarate occurs during Kreb's cycle. This reaction is catalyzed by the enzyme succinate dehydrogenase and is accompanied by the reduction of one molecule of oxidized FAD to reduced FADH${}_2$.
• The reduced coenzymes produced during the Kreb's cycle are oxidized subsequently by mitochondrial electron transport when ATP is produced. One molecule of reduced FADH${}_2$ when oxidized by mitochondrial electron transport system results in the synthesis of 2 molecules of ATP.
• So, the correct answer is option B.