Periodate-induced lipid oxidation of erythrocyte membranes

Exposure of human erythrocyte ghosts to 0.2-5 mM periodate at 0 C for 15 min resulted in an increase of thiobarbituric acid-reactive substances and fluorescent materials in the membrane. This increase was suppressed by radical scavengers, butylated hydroxytoluene and thiourea, indicating that periodate caused lipid oxidation of ghosts. A role of hemoglobin in the periodate-induced lipid oxidation of ghosts was suggested by the fact that the oxidation was augmented by hemoglobin and inhibited by an iron chelator, desferrioxamine. Treatment of ghosts with periodate caused membrane protein cross-linking with and without disulfide bridge. Erythrocytes were also susceptible to lipid oxidation by periodate, but only disulfide-mediated protein cross-linking was observed. Erythrocytes treated with neuraminidase or trypsin were less susceptible, but those treated with neuraminidase along with galactose oxidase were nearly as susceptible as untreated cells. The effect of galactose oxidase was diminished by reduction of the enzyme-treated cells with borohydride. These results indicate that the aldehyde moieties generated by periodate at the sialyl residues or those generated by galactose oxidase at the terminal galactosyl or N-acetyl galactosaminyl residues of the membrane glycoconjugates play a stimulating role in the periodate-induced membrane lipid oxidation.