Receptor Proteins for Concanavalin A and Wheat Germ Agglutinin of Bovine Milk Fat Globule Membrane Probed by Affinity Chromatography in the Presence of Sodium Dodecyl Sulfate

Abstract

The receptor proteins for lectins of bovine milk fat globule membrane were probed by affinity chromatography on Concanavalin A (ConA)- and wheat germ agglutinin (WGA)-Sepharose in the presence of sodium dodecyl sulfate. Affinity chromatography on lectin column distinguished minor differences of specificity for lectin in a glycoprotein having the same mobility on electrophoresis. Of seven major glycoproteins (PAS-1 to 7), PAS-1 and -2 were bound to both Con A and WGA. Most of PAS-3 was retained on Con A. PAS-4 was retained on both WGA and Con A. A striking difference was observed between PAS-6 and -7 glycoproteins in the affinity to Con A, that is, PAS-6 was bound to Con A while PAS-7 not retained on Con A. However, most of PAS-6 and -7 was not retained on WGA, Part of PAS-5 was bound firmly while other parts failed to bind to both Con A and WGA. Our results suggest that the structure of saccharide chains of the glycoproteins of MFGM is very complicated.