So the rate of chemical reactions depends on its activation energy and enzymes increase the rates of reactions by decreasing the activation energy. The activation energy is the amount of energy that must be added to our system, to our reaction, to transform the reactants to the transition state and then to our products. So basically, this is the first important point that we must know about enzymes. So enzymes increase the rate of the full reaction, but they also increase the rate of the reverse reaction. So this is a very important point that most people sometimes miss. So if we look at the following diagram, we have the full reaction going this way and we also have the reverse reaction going this way.