HIGH-PERFORMANCE ELECTROPHORESIS CHROMATOGRAPHY OF BOVINE-MILK COMPONENT-3 GLYCOPROTEINS

Component 3 corresponds to the hydrophobic fraction of bovine milk pro teose-peptone and is composed of three principal glycoproteins with mo lecular masses of 11, 19, and 29 KDa. To understand better its interes ting emulsifying properties and its capability of inhibiting spontaneo us lipolysis in milk, isolation and characterization of the three glyc oproteins are needed. The newly introduced technique of high performan ce electrophoresis chromatography is an efficient tool to prepare thes e glycoproteins in high purity. This preparative technique offers the resolving power of gel electrophoresis with the automatization associa ted with HPLC. Parameters that influence protein separation are discus sed. The isolated 19- and 29-kDa glycoproteins, which bind to immobili zed concanavalin A, are then characterized by analysis of their glycan and amino acid compositions. In particular, the glycan molar ratio of the 19-kDa glycoprotein is in good agreement with a biantennary N-ace tyllactosamine-type glycan structure.