From Table , it can be seen that for all systems modeled here, the calculated values are within 1.5 kcal mol -1 deviation at most from the corresponding experimental values, with similar standard error of the mean on the calculated activation free energies from the conventional and replicaexchange EVB simulations. When looking at the distribution of the calculated activation and reaction free energies (Figure ) across the different systems and simulation lengths, it can be seen that there is no clear trend in either activation or reaction free energies across different systems and simulation times, but all values typically fall within a relatively narrow energetic range of +/-0.6 kcal mol -1 , occasionally with longer tails on the distribution. The average values remain stable across the different simulations. In the case of the reaction free energy, ΔG0, however (Table ), it appears that increasing simulation time can affect average calculated ΔG0 by several kcal mol -1 , and therefore the additional sampling time becomes important, in particular for multi-step reactions where the energetics of each subsequent step are dependent on correctly calculating the reaction free energy of the prior step.