[Effects of reactive species of oxygen and nitrogen on iron ion release from ferritin and synthesis of dinitrosyl iron complexes].

Using EPR spectroscopy it was established that Fe ions released from ferritin under the action of glutathione and superoxide took part in the formation of dinitrosyl complexes of iron with glutathione (DNIC). The reaction between O2-. and NO resulted in the formation of peroxynitrite, which oxidized glutathione to the thiyl radical. In these conditions, DNIC did not inhibit the formation of thiyl radicals but effectively slowed down the oxidative destruction of beta-carotene by peroxynitrite and free radicals of lipids. In the presence of glutathione, the inversion of the antioxidant properties of DNIC into prooxidant ones took place. S-nitrosoglutathione prevented this inversion and suppressed the free-radical oxidation of beta-carotene induced by ferritin. It was proposed that the equilibrium between S-nitrosoglutathione, DNIC, "free Fe" ions and ferritin may determine the balance between prooxidant and antioxidant processes in living organisms.