Antioxidant Activities of Different Hemoglobin Derivatives

Abstract The antioxidant activity of hemoglobin was examined by studying both its peroxidase activity and its interaction with the superoxide anion. The peroxidase activity of both the subunits (α and β) was reduced with respect to the α 2 β 2 tetramer and heme-oxidation was found to be associated with a decrease in this activity. Lucigenin-amplified chemiluminescence experiments have shown that at low pH, the presence of hemoglobin reduces the level of superoxide anion generated by the xanthine/xanthine oxidase system (met-Hb is more efficient in reducing the level of O − 2 than oxy-hemoglobin). These results confirm that hemoglobin may be of importance in providing protection against oxidative damage to erythrocytes.