And so once again, as we'll see in more detail in a future lecture, the apex of this curve describes the energy of the transition state. Now, what exactly does the enzyme do and how does the enzyme affect the activation energy? So we said previously that the enzyme does not change the Gibbs free energy of the reaction. It has no effect on the energy of the reactants and the products. And so their difference, the Delta G is exactly the same. It remains unchanged when the enzyme acts on that chemical reaction.