Quantitative studies of the energetics of enzymatic reactions and the corresponding reactions in aqueous solutions indicate that charge stabilization is the most important energy contribution in enzyme catalysis. Low electrostatic stabilization in aqueous solutions is shown to be consistent with surprisingly large electrostatic stabilization effects in active sites of enzymes. This is established quantitatively by comparing the relative stabilization of the transition states of the reaction of lysozyme and the corresponding reaction is aqueous solution.