The QM optimizations were performed using the UB3LYP/def2-SVP level of theory followed by a single point energy calculation using UB3LYP/def2-TZVP as a higher level of theory. The basis set and QM theory were employed here based on similar previous studies in P450 chemistry. The energetics were further improved using ZPE (zero-point energy) corrections followed by frequency calculations of optimized reactants (RC), transition state (TS), and product (PC) geometries at the UB3LYP/def2-SVP level of theory. Grimme dispersion (G-D3) was used to add dispersion correction in energetics. The part of protein and water molecules residing up to 8 Å from the QM zone were considered as active atoms and their electrostatic, as well as van der Waal effects, were accounted for by QM calculations. Moreover, an electronic embedding scheme was employed to account for the polarizing effect of the enzyme environment on the QM region. While treating the QM/MM boundary, we used hydrogen link atoms with the charge-shift model.