Superoxide radicals in the metabolism of the red cell

The formation of O2- radicals as primary products of O2 reduction by human erythrocytes is demonstrated. O2- radicals react directly with GSH and OxyHb as 1e-donors forming GSSG and MetHb. After exhaustion of the glutathione system MetHb increases greatly and secondary radicals formation ensues with breakdown of Hb. The toxicity of O2- radicals is caused mainly by secondary radicals.