This state of maximum energy is called the transition state. At this point, the system has enough energy to move from reactants to products. The reaction profile for the second step is shown in Figure 57, which shows that the transition state has the hydroxide partially bonded to the carbon. Finally, Figure 58, where we show the reaction profile for the whole reaction, makes it clear that the transition state for the first state is higher than that for the second step. The activation energy, which in this case is the energy required to reach the first transition state, is a very important part of the mechanism.
Catalysts increase the rate of a reaction by providing a pathway that has a lower activation energy.
Enzymes are biological catalysts that we depend upon to hasten the thousands of reactions that are constantly occuring in our bodies.