Binding properties of spectrin to thalassemic red cell membranes

Abstract

The underlying cause of pathology in thalassemia is the premature destruction of erythrocytes both in the bone marrow and the reticuloendothelial (RE) system. This is believed to result from oxidative stress caused by excess globin chains lying at the cytosolic face of the membrane. Binding study of normal spectrin to spectrin-depleted red cell vesicles was performed to investigate the properties of red cell membrane in a group of 3 patients with Hb H disease, Hb H in conjunction with Hb Constant Spring and beta-thalassemia/Hb E disease, together with 6 control normal subjects. Thalassemic red cells had the same ability to form vesicles as control and the protein compositions as analyzed on sodium dodecyl-sulfate polyacrylamide gel electrophoresis were also similar. Normal red cell vesicles showed a binding capacity of 96±10 ug/mg membrane protein with an affinity of 6.0±2.0 ug/ml or 12.9±4.4 nM. No differences in these parameters were detected between the thalassemia calls and control. It is concluded that specific binding site of ankyrin for spectrin in thalassemic red cell has not been affected by the presence of excess chains.