New Insights into the Chemistry and Functions of Coenzyme Q
The oxidative phosphorylation is a crucial physiological process that leads to energy production in the living cells. In this processes, Coenzyme Q10 acts as a redox mediator in the mitochondrial membrane, where it facilitates the electron transfer between the complexes I, II and III, while transfering protons across the inner mitochondrial membrane. We have recently shown that Coenzyme Q undergoes structural changes in highly alkaline media, but also in neutral media in presence of Cytochrome P-450 enzymes. The chemical reactions of Coenzyme Q with NaOH or with Cytochrome P-450 lead to scission of one or two methoxy groups from the Coenzyme Q structure, while giving as products hydroxyl derivatives of Coenzyme Q. The new hydroxylated Coenzyme Q derivatives have a chemical potential to bind Ca2+ and other earth-alkaline cations, and to transfer them across biomimetic membranes. Additionally, the newly synthesized hydroxyl Coenzyme Q derivatives can act as powerful antioxidants. The findings elaborated in this lecture explicitly show that the processes in the mitochondrial electron transfer chain can be switched in another direction under certain physiological conditions.