Inhibitors are substances that interfere with the function of enzymes either directly or indirectly.They may bind to the active site preventing the formation of enzyme substrate complexes or they may bind to an allosteric site resulting in a change the shape of the active site so that the substrate is unable to bind.Competitive inhibitors have a shape similar to the shape of the substrate so they are also able to bind to the active site. Like the substrate, their shape is complementary to the shape of the active site.The molecules of inhibitor compete with the substrate for the active site of the enzyme so fewer enzyme-substrate complexes are formed.If the substrate concentration is increased, the inhibitor has less of a chance to bind to the active site.At very high substrate concentrations, the effect of the inhibitor is reduced and the rate of reaction approaches Vmax.
