Selective alteration of erythrocyte deformability by SH-reagents. Evidence for an involvement of spectrin in membrane shear elasticity

摘要: Abstract In order to elucidate the molecular basis of membrane shear elasticity, effect protein modification by SH-reagents on deformability human erythrocytes was studied. Deformability quantified measuring elongation subjected viscometric flow in a transparent cone-plate viscometer. Impermeable proved have no mechanical effect. Many, but not all, permeable markedly decreased elongation. Among these, bifunctional (e.g. diamide, tetrathionate and N,N′-p-phenylenedimaleimide) able cross-link SH-groups were more effective than monofunctional N-ethylmaleimide ethacrynic acid). The produced 50% decrease after less 5% SH-groups. contrast, for comparable effect, 20% had be modified reagents. SH-oxidizing agents fully reversible treatment with disulfide-reducing agents. All induced dimerization small fraction spectrin. Analysis distribution diamide-induced disulfide bonds among various fractions showed that this agent preferentially acts spectrin polypeptides. results provide direct experimental evidence native arrangement is essential resistance erythrocyte introduction numbers intermolecular cross-links as well within molecule lead rapid loss function.