Question

Select the option which is not correct with respect to enzyme action.

• A. Malonate is a competitive inhibitor of succinate dehydrogenase.
• B. The addition of a lot of succinates does not reverse the inhibition of succinate dehydrogenase by malonate.
• C. A non competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate.
• D. The substrate binds with enzymes at its active site.

Answer 1

The correct option is B

The addition of a lot of succinates does not reverse the inhibition of succinate dehydrogenase by malonate.

The correct option is B.

Explanation of correct option:

1. The effect of a competitive inhibitor can be minimized by adding an excess substrate molecule.
2. This is because if the substrate concentration is more than that of the competitive inhibitor, greater number of substrate molecules in comparison to the competitive inhibitor can bind with the enzyme.
3. Therefore, the addition of more succinate reverses the inhibition of succinate dehydrogenase enzyme by malonate.

Explanation of incorrect options:

Option A:

1. Succinate dehydrogenase enzyme converts succinate to fumarate.
2. It is competitively inhibited by malonate which is structurally similar to succinate.

Option C:

A non-competitive inhibitor binds to the enzyme at the site where catalysis takes place other than the substrate-binding site.

Option D:

The active site of an enzyme is the site of an enzyme at which the substrate binds.

Final answer: The incorrect option is the addition of a lot of succinates does not reverse the inhibition of succinate dehydrogenase by malonate.