Ss blood group associated PAS-staining polymorphism of glycoprotein 3 from human erythrocyte membranes

It is shown by discontinuous sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis of human red cell membranes, followed by periodic acid Schiff (PAS) staining and densitometry, that the band PAS-3 (monomeric Ss glycoprotein) exhibits a polymorphism with respect to its staining intensity. In membranes of the genotype SS the staining intensity of this band is about 1.5 times higher than in ss membranes. The experimental error of the method does not permit one to decide, whether membranes of blood type Ss exhibit an intermediate staining intensity or not. The SDS electrophoretic molecular weight of PAS-3 is the same for SS, Ss, or ss membranes. The ratio of PAS to coomassie blue staining intensities, which are a measure of sialic acid and protein content, respectively, are equal for PAS-3 in glycoprotein preparations from SS and ss erythrocytes. These data indicate that the above phenomenon reflects a difference in the glycoprotein content between SS and ss membranes.