Explain the effect of inhibitors on the activity of enzymes.

Enzyme inhibitors are substances that alter the catalytic action of an enzyme. There are two types of inhibitors: competitive and non-competitive. Competitive inhibitors bind at the active site of an enzyme and so slow down its action by preventing substrates from binding to it. By increasing the concentration of substrate, the activity of the enzyme is increases, since there is a higher probability of the substrate binding to the enzyme rather than the competitive inhibitor. The other type of inhibitor is the non-competitive one. This type of inhibitor binds to an alosteric site of the enzyme (meaning not at the active site, but somewhere else). The effect that this has is that the substrate can no longer bind to the enzyme because its shape has been changed by the binding of the inhibitor.