The Synergetic Coupling among the Cellular Antioxidants Glutathione Peroxidase/Peroxiredoxin and Other Antioxidants and its Effect on the Concentration of H2O2

Glutathione peroxidase (GPx), peroxiredoxin (Prx), and catalase are the major antioxidants at the cellular level and protect cell compartments against hydrogen peroxide (H2O2). In addition, they affect cellular processes such as cell signaling by modulating H2O2. In this paper we demonstrate that there is a synergetic coupling between GPxs, Prxs themselves and also with other antioxidants when the GPxs and Prxs are not in their saturated reduced form. This is due to a change in the activity of glutathione peroxidases and peroxiredoxins as a result of a change in the concentrations of other antioxidants. The strength of this synergy depends on the reaction rates and the concentration of these antioxidants. We use a perturbative method to calculate the concentration of H2O2 as function of the production rate of H2O2 and the concentration of various antioxidants. This derivation shows clearly why antioxidants behave in a correlated manner and why any change in the activity of one of them translates to a change in the activity of other antioxidants. Our results show that an increase in the activity of GPxs or Prxs might not be due to a genetic switch but due to an increase in the activity of other antioxidants.