The inhibitor-bound complex forms mostly under concentrations of high substrate and the ES-I complex cannot release product while the inhibitor is bound, thus result in reduced Vmax. ... Thus, paradoxically, uncompetitive inhibition both decreases Vmax and increases an enzyme's affinity for its substrate.

How does noncompetitive inhibitor affect Vmax?

When a non-competitive inhibitor is added the Vmax is changed, while the Km remains unchanged. According to the Lineweaver-Burk plot the Vmax is reduced during the addition of a non-competitive inhibitor, which is shown in the plot by a change in both the slope and y-intercept when a non-competitive inhibitor is added.

Why is the Vmax lowered in noncompetitive inhibition?

For the competitive inhibitor, Vmax is the same as for the normal enzyme, but Km is larger. For the noncompetitive inhibitor, Vmax is lower than for the normal enzyme, but Km is the same. ... The extra substrate makes the substrate molecules abundant enough to consistently “beat” the inhibitor molecules to the enzyme.