But the concentration of reactants and products is exactly the same. It's unchanged at equilibrium. So equilibrium is reached faster, but the actual concentrations of the reactants and products at equilibrium does not change. Now let's move on to the third important fact about enzymes. So, biological enzymes, biological catalysts do not change the energy of the products, nor do they actually change the energy of our reactants. And that means the change in enthalpy or the change in Gibbs free energy of the overall reaction does not exactly change.