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 (SDH) is an enzyme with a dual role in metabolism, functioning in both the Krebs cycle (citric acid cycle) and the electron transport chain (ETC). In the Krebs cycle, SDH catalyzes the oxidation of succinate to fumarate. Concurrently, in the ETC, it transfers electrons from FADH2 to ubiquinone (coenzyme Q). SDH is uniquely the only enzyme embedded in the inner mitochondrial membrane, thereby linking these two major energy-producing metabolic processes.