Crosslinking of glycoproteins in human erythrocyte ghosts

Abstract

Membrane glycoproteins of human erythrocytes can be resolved into three major bands (GP-1, GP-2, and GP-3) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When the ghosts or intact erythrocytes were reacted with a crosslinking reagent, dimethyl malonimidate, a novel glycoprotein band (GP-A) of crosslinked product appeared on gel electrophoretograms of the solubilized membranes. When the crosslinked glycoproteins (GP-A) were ammonolyzed to cleave the crosslinks and subjected again to electrophoresis, on fresh gels, two glycoprotein bands (GP-1 and GP-2) were produced. It is concluded that GP-1 and GP-2 were crosslinked to form GP-A in the membrane. Only a small fraction of the glycoproteins was crosslinked, even after the ghosts were reacted with excess amounts of the reagent and for extended periods of time of crosslinking.