Imagine that you synthesize a molecule that resembles the substrate of a particular enzyme but has a different chemical composition. You discover that this "substrate imposter" can bind to the enzyme's active site. What effect will the "substrate imposter" have on the reaction that is normally catalyzed by the enzyme?

The synthesized substrate can either mimic the natural substrate, which means the synthesized substrate functions as a catalyst, resulting in a bigger or faster reaction. Or the synthesized substrate can block the moleculair binding site for the natural substrate, then it functions as an inhibitor, resulting in a smaller or slower reaction or even preventing a reaction at all.