Question

Which of the following enzymes of Krebs’ cycle is also involved in the mitochondrial electron transport system?

• A. Citrate synthase
• B. Succinate dehydrogenase
• C. Malate dehydrogenase
• D. Isocitrate dehydrogenase

Hint:

Succinate dehydrogenase is a membrane-bound enzyme that oxidizes succinate to fu- marate in the Krebs cycle and also transfers electrons from FADH2 to ubiquinone (coenzyme Q) in the electron transport chain.

Answer 1

The Correct Option is B

Succinate dehydrogenase is an enzyme that is involved both in the Krebs cycle (citric acid cycle) and the electron transport chain (ETC). In Krebs cycle, succinate dehydrogenase catalyzes the oxidation of succinate to fumarate and at the same time in the ETC, it transfers the electrons to FADH2 to ubiquinone (coenzyme Q). This is the only enzyme that is embedded in the inner mitochondrial membrane, linking two major energy producing metabolic processes.