Question

Which statement regarding enzyme inhibition is correct?

• A. Competitive inhibition occurs when a substrate competes with enzyme for binding to inhibitor protein
• B. Competitive inhibition occurs when the substrate and the inhibitor compete for 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 occurs when the substrate and the inhibitor compete for active site on the enzyme

A molecule similar to substrate competes with the substrate for active site. Such molecules are known as 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.

For example, malonate acts as a inhibitor which competes with the succinate and prevents its attachment to the enzyme succinate dehydrogenase.

So, the correct answer is option B.