Cross-linked hemoglobin-superoxide dismutase-catalase scavenges oxygen-derived free radicals and prevents methemoglobin formation and iron release.
In this study, we prepared PolyHb-SOD-catalase (intermolecularly cross-linked hemoglobin, superoxide dismutase (SOD), and catalase). We found that PolyHb-SOD-catalase is effective in scavenging oxygen-derived free radicals. In the xanthine/xanthine oxidase system, the initial rate of cytochrome c reduction was 2.13 +/- 0.26 nmoles cyt. c/min for PolyHb alone. PolyHb- SOD-catalase reduced this to 0.56 +/- 0.08 nmoles cyt. c/min because of its ability to eliminate superoxide (O2-). Addition of PolyHb to 200 microM of hydrogen peroxide (H2O2), changed the H2O2 level slightly to 192 +/- 0.4 microM. Addition of PolyHb-SOD-catalase, on the other hand, lower the level to 41 +/- 0.3 microM. Results also show that both effects were dependent on the concentration of SOD-catalase cross-linked with hemoglobin. Oxidative challenge with H2O2 resulted in minimal changes in the absorbance spectra of PolyHb-SOD-catalase. With PolyHb, there were spectral changes reflecting the formation of methemoglobin and heme degradation. Furthermore, the amount of iron released, after incubation with 250 microM H2O2, was 6.8 +/- 1.8 micrograms/dl for PolyHb-SOD-catalase and 76.6 +/- 1.0 micrograms/dl for PolyHb. These results show that cross-linked SOD-catalase prevents oxidative reactions involving the hemoglobin component of PolyHb-SOD-catalase.
D'Agnillo
F
F
Artificial Cells and Organs Research Centre, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
Chang
T M
TM
D002374:Catalase / Q000494:pharmacology*; D003432:Cross-Linking Reagents; D016166:Free Radical Scavengers; D006454:Hemoglobins / Q000378:metabolism / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D008706:Methemoglobin / Q000096:biosynthesis; D009097:Multienzyme Complexes / Q000494:pharmacology*; D010084:Oxidation-Reduction; D013482:Superoxide Dismutase / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism
D003432:Cross-Linking Reagents; D016166:Free Radical Scavengers; D006454:Hemoglobins; D009097:Multienzyme Complexes; C037158:polyhemoglobin; D013481:Superoxides; D008706:Methemoglobin; D006861:Hydrogen Peroxide; D007501:Iron; D002374:Catalase; D013482:Superoxide Dismutase; C086134:polyhemoglobin-superoxide dismutase-catalase