Question

Which one of the following statements regarding enzyme inhibition is correct?

• A. Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.
• B. Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.
• C. Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate.
• D. Non-competitive inhibitors often bind to the enzyme irreversibly.

Answer 1

The correct option is B Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.

Competitive inhibitor resembles the natural substrate and combines reversibly or irreversibly to the free enzyme at the active site. Thus, there is a competition between substrate and inhibitor for the active site of enzyme. Example : Malonate inhibits succinate dehydrogenase activity because its structure is similar to succinate.

So, the correct answer is 'Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.'