Fig. 4. Percentage of membrane -SH groups measured in untreated erythrocytes, or Mg²⁺-treated (control) or treated with either 300 μM or 600 μM or 1 mM H₂O₂ with or without 10 mM Mg²⁺ (10 mM Mg²⁺+ 300 μM H₂O₂ or 10 mM Mg²⁺+ 600 μM H₂O₂ or 10 mM Mg²⁺+ 1 mM H₂O₂). Bars represent the mean ± SD from at least 5 experiments, where 10 mM Mg²⁺ n.s. versus untreated erythrocytes; n.s. versus control.