A researcher adds a molecule to an enzyme-catalyzed reaction and observes that the reaction rate decreases. Increasing the substrate concentration cannot restore the original reaction rate. Which statement best explains this observation?

Core Concept

A noncompetitive inhibitor binds at a location other than the active site, altering the enzyme's shape and reducing its catalytic efficiency. Because the inhibitor does not compete with the substrate for the active site, adding more substrate cannot reverse the inhibition.