Question

The activity of succinate dehydrogenase is inhibited by

• A. Malonate
• B. Pyruvate
• C. Glycolate
• D. Phosphoglycerate

Answer 1

Answer: (A)

Malonate

A molecule similar to substrate competes with the substrate for the active site. Such molecules are known as the inhibitor. The presence of the inhibitor decreases availability of the active site for the substrate and further decreases the rate of reaction. This inhibition is known as competitive inhibition.

Succinate dehydrogenase is an enzyme which is present in the inner mitochondrial membrane. It catalyzes the oxidation of succinate to fumarate. It is a conjugated protein as it has flavoprotein which has FMN or FAD molecule as a prosthetic group. Malonate acts as an inhibitor which competes with the succinate and prevents its attachment to the enzyme.

So, the correct answer is option A.