Figure 2. A, Electron paramagnetic resonance (EPR) spectra of 5-doxyl stearic acid in erythrocyte membranes in the presence of gradually increasing H₂O₂ concentrations. The vertical dotted lines are references for the control value of the 2A_// parameter, the outer hyperfine splitting. The total scanning range of the magnetic field of all spectra was 100 G. B, EPR parameter, 2A_//, for the control (squares), the 160-µM ascorbic acid-treated (circles) and the 300-µM α-tocopherol-treated (stars) samples as a function of H₂O₂ concentration.