Effect of diamide on protein oxidation and physico-chemical properties of lipids in erythrocyte membranes
Kozlova, N.M.; Luk'ianenko, L.M.; Antonovich, A.N.; Kut'ko, A.G.; Zubritskaia, G.P.; Slobozhanina, E.I.
Biofizika 47(3): 500-505
2002
ISSN/ISBN: 0006-3029 PMID: 12068607 Document Number: 549308
The effect of diamide on the physicochemical state of proteins and lipids of human erythrocyte membrane was studied. It was found that diamide at a concentration of 1 mM decreases the content of the SH-groups of membrane proteins by approximately 50%, resulting in enhanced vesiculation of erythrocytes upon metabolic exhaustion of cells. It was shown using fluorescein isothiocyanate-labeled concanavalin A and 4,4'-diisothiocyano-2,2'-stilbene disulfonate that diamide changes the structural state of the main integral protein of erythrocyte membranes, the band 3 protein. Changes in the microviscosity of the membrane lipid bilayer depending on diamide concentration were determined from the changes in the fluorescence parameters of the lipophilic probes (pyrene and 1,6-diphenyl-3,5-hexatriene). The level of lipid peroxidation products in membranes remained unchanged. It follows from these data that the SH-oxidizing agent diamide does not directly interact with the lipid bilayer of membrane and produces changes in the physicochemical state of lipids presumably by disrupting protein-lipid interactions that take place upon oxidation of the SH-groups and cross-linking of membrane proteins.