The initial coordinates for these enzymes were taken from the crystal structures with PDB IDs: 1JPZ (CYP450BM3), 24 4L4O (CYP450OleT) , and 1IZO (CYP450BSβ). These structures were cocrystalized with the following substrates: N-Palmitoglycine (NPG) in CYP450BM3, Icosanoic acid (DCR) in CYP450OleT, and Palmitoloeic acid (PAM) in CYP450BSβ. Missing hydrogen atoms and some heavy atoms were added by the leap module of Amber 20. The force fields for the heme moiety were taken from the already published parameters for the Cpd I state. The Amber ff19SB force field was employed for all the enzymatic systems. The associated partial atomic charges and missing parameters for the substrates were generated by applying the restraint electrostatic potential (RESP) method of QM calculated charges at the HF/6-31G(d) level of theory. The corresponding parameters for substrates were generated using Generalized Amber Forcefields (GAFF2) in the Antechamber module of Amber 20. A few Na+ ions were added to the protein surfaces to neutralize the total charge of the system. Finally, the resulting systems were solvated in an octahedral box of three different water models: TIP3P, OPC, and SPC/E, each extended up to a minimum cut-off of 10 Å from the protein boundary. The catalytic cycle of CYP450 has many states. However, here we focus on the Cpd I state which is the ultimate oxidant species that leads to catalyze the substrate.