Question

What would happen to V${}_{max}$, in the presence of a non-competitive inhibitor?

• A. It decreases
• B. It increases
• C. Remains the same
• D. First increase then decrease

Answer 1

The correct option is A It decreases

In non-competitive inhibition, the inhibitor molecules do not compete with the substrates for active sites on the enzyme surface, but some other site on the enzyme. This results in a decrease in the enzyme molecules that can catalyse the reaction. Hence,
V${}_{max}$ is lowered. As a result, the non-competitive inhibitors cannot be completely overcome by the addition of more substrate. This leads to a decrease in V${}_{max}$ of the reaction.