Question

In a competitive inhibition, Km is increased while Vmax is unchanged. An enzyme is being assayed in the presence of a fixed amount of a competitive inhibitor. How could the rate be increased in this reaction?

Answer 1

Ans. As mentioned, Vmax remains unaffected while Km is increased in presence of a competitive inhibitor.

# The rate of enzyme catalyzed reaction in presence of a competitive inhibitor may drop down below Vmax because of increased Km (the inhibitor competes with substrate for the enzyme. So, lesser substrate molecules bind to enzymes in presence of inhibitor, thus leading to a reduction in un-inhibited Vmax).

# To rate of reaction in presence of inhibited can be RESTORED (reaction velocity can never go above Vmax unless [E] is increased) to un-inhibited Vmax by increasing substrate concentration [S]. If [S] is sufficiently increased, the inhibitor molecules can no longer bind to enzyme because of their significantly low content- and Vmax is restored.

Or, the rate of inhibited enzyme reaction can be increased to un-inhibited Vmax by increasing [S].