A substance binds to an enzyme to decrease the apparent Km for the substrate. This substance will
A) be an inhibitor at low substrate concentration.
B) be an inhibitor at any substrate concentration.
C) be an activator at substrate concentrations below saturation.
D) be an activator only when the substrate is present at a saturating concentration.
E) interfere with substrate binding.

Question

Quizplus · Accepted Answer

This substance is decreasing the apparent Km for the substrate, which means that the enzyme is becoming more efficient at binding the substrate. This suggests that at lower substrate concentrations, the substance is acting as an activator, making it easier for the enzyme to bind the substrate. However, at higher substrate concentrations, the enzyme will likely reach saturation and the substance may no longer have an effect on the reaction rate.

A Substance Binds to an Enzyme to Decrease the Apparent