The Asparagine-Linked Sugar Chains of Plasma Membrane Glycoproteins of K-562 Human Leukaemic Cells: A Comparative Study with Human Erythrocytes1

Abstract

The paper electrophoretic pattern of the oligosaccharides released from the plasma membranes of K-562 cells by hydrazinolysis was quite different from that of human erythrocyte membranes. Bio-Gel P-4 column chromatography in combination with sequential exoglycosidase digestion of the neutral oligosaccharide fractions revealed that all those from K-562 cells are of the high mannose type, while those from erythrocytes are of large complex type structures. Studies of the acidic oligosaccharides indicated that none of those obtained from K-562 cells contained the beta-N-acetylglucosamine residue linked at the C-4 position of the beta-mannosyl residue of the trimannosyl core, which occurs in most of the asparagine-linked sugar chains of human erythrocytes. This indicates that the glucosaminyltransferase that forms the GlcNAc beta 1 leads to 4Man beta 1 leads to group has not been expressed in K-562 cells.