Computer simulation of interaction of superoxide ion with active centers of SOD and cytochrome C in low-sized cell membranes

The article compares the effectiveness of neutralization of the active form of oxygen (superoxide radical ion) by two antioxidant enzymes—Cu, Zn-superoxide dismutase and cytochrome c. The basic characteristics of electron transfer between the superoxide radical and the active centers of enzymes were obtained using the software package of quantum mechanical calculations by Orca and the density functional theory at the B3LYP/6-31G(d, p) level. Additionally, the influence of the dielectric constant of the electron transfer medium was considered. With the application of the Marcus theory and the four-point method, the energies of the system reorganization and the activation energy of electron transfer were obtained. The results of computer simulation have shown that an increase in the dielectric constant of the medium negatively affects the efficiency of neutralization of the radical. The high antioxidant activity of superoxide dismutase in comparison with cytochrome c has been proven.