We quantified the electric field exerted by enzyme along C-O bond (see Figure and) of the substrate to probe the electric field effect. For doing so, we used the optimized structures from the QM/MM calculations as mentioned above. Our calculations show a net electric field of -0.2 V/Å directed along of reaction centre in the the C-O axis at the site absence of solvent molecules (LEF of enzyme alone) while it is -0.53 V/Å in presence of solvent molecules (see Figure and). To further justify the effect of electric field of enzyme on the catalysis, we performed the gasphase DFT calculations in the presence of external electric field of the same order of intensities exerted by the enzyme as calculated above. Figure As we have seen that prephenate conversion from chorismate in absence of any enzymatic environment (i.e., in gas phase, c.f. Figure ) is highly unfavorable, however, at electric field of -0.54 V/Å which is EF of the enzyme, the TS barrier surprisingly reduces to ~19.0 which is relatively closer to the TS barrier in enzymatic environment calculated by QM/MM method. To be more precise, we also calculated the effect of EEF on the dipole moments (see SI). It is quite apparent that the dipole moments of TS along the Y-axis are positively signed which further increases towards positive scale on increasing the magnitude of EEF along the negative direction of y-axis. Hence, we can speculate that the application of EEF polarizes the TS in favourable manner and in turn decreases the TS barrier. The effect of EEF on dipole and hence on the activation energy, can also be validated by applying EEF in opposite direction. As can be seen form Figure , the reversal of the direction of external electric field with magnitude 0.2 V/Å increased the TS barrier to 65.78 kcal/mol, which is almost double of the observed in absence of EEF. The TS dipole moment due to reversal of the EEF is also decreased to 13.03 Debye, thereby, validating the effect of TS polarization of the reaction barrier. These results of the applications of external electric field that mimic the EF of enzymatic environment elucidate that the catalysis observed by the Bacillus subtilis chorismate mutase enzyme is electric field induced catalysis i.e., it uses its local electric field (LEF) to enhance the reaction million-folds. Furthermore, these results provide a qualitative agreement to the fact that protein environment of the enzyme produces a favorable electric field for the Claisen rearrangement reaction despite no covalent participation of protein residues.