Heterogeneity of glycoproteins of the human erythrocyte membrane.  Fractionation in sodium dodecyl sulfate containing solutions. 
Human erythrocyte membranes and the glycoprotein isolated by phenol-water extraction of membranes were fractionated by gel filtration on Bio-Gel P-300 in 1% SDS.  It was shown by this procedure that lipids (and possibly other membrane components) promote the dissociation of glycoprotein aggregates in SDS-containing solutions.  The isolated glycoprotein gives several fractions on gel filtration in 1% SDS.  The main fraction contains the major sialogylcoprotein (MN), which can be obtained in an electrophoretically homogeneous form (PAS-1) when only a part of the major peak is pooled and re-chromatographed.  The purified glycoprotein has elevated MN blood group activity, does not show I activity, and contains components of alkalibabile oligosaccharide chains in slightly higher proportion than crude glycoprotein.  The other fractions have distinctly different carbohydrate composition and contain glycoproteins of different electorphoretic mobility in SDS-PAGE.