[Isolation and determination of the molecular mass of the RHoD antigen in human erythrocytes]

RhoD antigen was isolated from human erythrocytes using membrane solubilization by 2-mercaptoethanol and nonionic detergents BRIJ 35. Initial treatment of membrane using water at pH 12, failed to solubilize D antigen, which proved that D antigen is an integral protein of erythrocyte membrane. D antigen molecule mass was investigated by ultrafiltration and gelfiltration. Molecular mass was determined by ultrafiltration in the range of 10-20 000 daltons, and by gelfiltration on Sephacryl S--200 as 32 700. Using gelfiltration on Sephadex G-25, D antigen molecular mass was determined to be less than 25 000 and was approximately 14 000 daltons. Discrepancy between those two ways of determination by gelfiltration and ultrafiltration could be explained by the possibility that D antigen globularity is practically unexpressed.