Mechanism of Free Radical-Induced Hemolysis of Human Erythrocytes: Comparison of Calculated Rate Constants for Hemolysis with Experimental Rate Constants

We previously developed a simple competitive reaction model between lipid peroxidation and protein oxidation in erythrocyte membranes that accounts for radical-induced hemolysis of human erythrocytes. In this study, we compared the rate constants calculated from the hemolysis curves of erythrocytes in the presence of radical initiators with those obtained from experiments using erythrocyte ghosts treated with radicals. 2,2′-Azobis(amidinopropane) dihydrochloride and 2,2′-azobis(2,4-dimethylvaleronitrile) were used as radical initiators. Plots of the logarithm of concentration of the radical initiator against the logarithm of the rate constant gave straight lines. The slope of the lines for the calculated lipid peroxidation was nearly equal with the experimental value. Similar results were obtained for oxidation of membrane proteins, except for band 3 oxidation. The values for the rate constants calculated from hemolysis curves seem to be accurate. The slope of the lines for the calculated rate constants for proteins was larger than the experimental value for band 3 oxidation, because band 3 oxidation is accompanied by aggregation or redistribution of band 3 proteins to form hemolytic holes. These results indicate that the competitive reaction model may be useful for analyzing radical-induced hemolysis.