High-Performance Gel-Permeation Chromatography of Bovine Skim Milk Proteins

The separation of bovine skim milk proteins by gel-permeation high performance liquid chromatography was examined. Toya-Soda TSK-GEL (Type SW) columns were used with an eluent of .05 M phosphate buffer (pH 6.80) containing .1 M sodium sulfate at .5 ml/min. Bovine whole milk was centrifuged to remove lipids, and the resultant skim milk directly injected. A 2000SW column yielded three protein peaks: 1 = casein, IgG and BSA; 2 = 6-lactoglobulins and BSA; and 3 = α-lactalbumin and BSA. A 3000SW plus 2000SW column system with a 30 μl injection volume yielded four protein peaks: 1 = minor amounts of α - and β-casein; 2 = casein, BSA and IgG; 3 = β-lactoglobulins; and 4 = α1-lactalbumin. A 3000SW plus 2000SW column system with a 10 μl injection volume yielded five protein peaks: 1 = casein; 2 = IgG; 3 = BSA; 4 = β-lactoglobulins; and 5 = α-lactalbumin. Both the single column and dual column applications yielded three nonprotein peaks, which were dialyzed from solution. Thus, a high speed analytical separation of milk proteins was achieved according to molecular size, but this application is highly dependent on sample size.