In competitive inhibition, what happens to Vmax?

In the context of competitive inhibition, Vmax remains unchanged because the inhibitor competes with the substrate for the active site on the enzyme. While the presence of a competitive inhibitor increases the apparent Km (Michaelis constant), which reflects a decrease in the enzyme's affinity for the substrate, it does not affect the maximum velocity (Vmax) that can be achieved by the enzyme.

This is because, in competitive inhibition, if enough substrate is present, it can outcompete the inhibitor, allowing the enzyme to reach its full reaction velocity. Therefore, at sufficiently high substrate concentrations, the effects of the inhibitor can be overcome, and the enzyme can still achieve its maximum reaction rate. Hence, Vmax is not altered by the presence of a competitive inhibitor, which is why the correct answer is that Vmax remains the same.