Fig. 10. Diagram for free energy versus reaction coordinate for E^A, TS and E^R in 0 and 20% glycerol.

A. Preferential destabilization of E^R by glycerol. The free energies for E^A in 20% and 0% glycerol (dashed and solid lines respectively) were first fixed at the same zero value with ΔG_(20–0) = 0 for the difference in free energy between E^A in 20 and 0 % glycerol. Preferential destabilization of E^R by glycerol was then modeled by lowering the free energy of E^R by the amount required by the K_R values in Table I using ΔG_AR(0%) = −RT ln(K_R(0%)) = −10.0 kJ/mole and ΔG_AR(20%) = −RT ln(K_R(20%)) = −3.6 kJ/mole. The free energy of the transition states were calculated from the velocity values in Table I using velocity = (k_BT/h)e^−ΔG╪/RT where k_B is the Boltzmann constant and h is the Planck constant. B. Preferential stabilization of E^A by glycerol. Calculated similarly to (A) but starting with the free energy of E^R in 0 and 20 % glycerol fixed at zero and glycerol preferentially stabilizing E^A.