What effect does competitive inhibition have on the rate of enzyme-catalyzed reactions?

Competitive inhibition is a phenomenon that occurs when an inhibitor mimics the substrate and binds to the active site of an enzyme. This process effectively competes with the substrate for binding. The presence of competitive inhibitors can alter the rate of an enzyme-catalyzed reaction in a distinct manner, particularly influenced by substrate concentration.

When substrate concentration is low, the competitive inhibitor binds to the enzyme, reducing the rate of the reaction because fewer enzyme molecules are available to bind with the substrate. However, as the concentration of the substrate increases, the likelihood of substrate molecules binding to the active site also increases. At sufficiently high substrate concentrations, the effect of the competitive inhibitor can be overcome, leading to a restoration of the reaction rate to that of the uninhibited enzyme environment.

Thus, while competitive inhibition initially decreases the reaction rate at low substrate concentrations, its effect diminishes as the substrate concentration rises, specifically causing a decrease in the reaction rate only at low levels of substrate. Therefore, competitive inhibition definitely impacts the reaction rate in this capacity, making the assertion that it decreases the rate only at high substrate concentrations correct.