In this report, we demonstrate the use of semiempirical quantum mechanics (QM) and molecular dynamics simulations (MD) in conjunction with the Frohlich-Kirkwood theory to calculate the dielectric permittivity of proteins. The proteins staphylococcus nuclease and T4 lysozyme were examined in order to investigate the structural basis of the macroscopic dielectric permittivity from microscopic simulations. Use of QM allowed a realistic representation of electronic polarizability of the proteins, which is otherwise inaccessible because of the use of fixed point charge models in the classical force fields which are typically used to study proteins. The key findings of this study were: dielectric permittivity is not a constant but varies with region of the protein, and its structural and electronic features. It is the highest in the surface and boundary regions and drops off sharply towards the interior of the protein. Electronic polarization, whether due to solvent, or to the protein environment significantly influences permittivity.