Our choice of Chorismate Mutase (CM) as a model system to study the electric field effect is based mainly due to its peculiar characteristic to catalyse reaction using electrostatic environment created by the protein without involvement of any covalent bonding, and therefore, the effect of electric field could be more prominent in CM. Furthermore, sufficient experimental studies for WT and its several variants are also available which can be used to benchmark the computational findings . In the same context, Hilvert group, using experimental gene engineering of the active site residues, emphasized the role of positively charged residue e.g., R90/K90 to stabilize the transition state (TS) of the charismatic rearrangement. This finding was further justified by site directed mutagenesis studies performed by the same group in a separate study where they mutated R90 with Alanine and Glycine, and found that the catalytic activity was decreased by 5-fold relative to WT complex. The activity was again restored when a Lysine residue was reinstated at the same position. These findings clearly confirm a crucial role of the electrostatic environment in the catalysis. In the present study, therefore, we have used WT chorismate mutase along with its variant to establish a linear correlation between enzymatic electric field and its catalytic efficiency using MD simulations, and hybrid QM/MM calculations. Using an example of Chorismate Mutase, we show that Electric field can be used as an efficient descriptor for the enzymatic activity.