Van Hekken D L, Thompson M P
Agricultural Research Service, Eastern Regional Research Center, Philadelphia, PA 19118.
J Dairy Sci. 1992 May;75(5):1204-10. doi: 10.3168/jds.s0022-0302(92)77868-0.
Optimal conditions were established for alkaline urea-PAGE using modified precast, ultrathin gradient gels on the automated PhastSystem. Profiles of milk proteins showed that the caseins and whey proteins resolved extremely well. Major bands were observed for alpha s1-casein and beta-casein, and alpha s2-casein appeared as a well-resolved doublet. In contrast, kappa-casein separated from other caseins as a faint doublet, and purified kappa-casein appeared as one major and one minor band. Whey proteins (serum albumin, alpha-lactalbumin, beta-lactoglobulin) separated into broad bands resolved from each other and from the caseins. Partially (40%) dephosphorylated whole casein showed multiple bands for alpha s1-casein and beta-casein at different levels of phosphorylation. Separation of genetic phenotypes was observed for beta-lactoglobulin A and B; alpha s1-casein A, B, and C; and beta-casein A, B, and C. Electrophoretic patterns of milk proteins extracted from cheese samples varied among the different types of cheeses. Our modified procedure provides researchers with a rapid technique to separate both caseins and whey proteins on the same urea gel according to their charge to mass ratios.
利用自动化的PhastSystem系统上改良的预制超薄梯度凝胶，建立了碱性尿素聚丙烯酰胺凝胶电泳（alkaline urea-PAGE）的最佳条件。乳蛋白图谱显示，酪蛋白和乳清蛋白分离效果极佳。观察到αs1-酪蛋白和β-酪蛋白的主要条带，αs2-酪蛋白呈现为一条分辨率良好的双峰带。相比之下，κ-酪蛋白与其他酪蛋白分离为一条微弱的双峰带，纯化的κ-酪蛋白呈现为一条主要条带和一条次要条带。乳清蛋白（血清白蛋白、α-乳白蛋白、β-乳球蛋白）分离为彼此分开且与酪蛋白分开的宽带。部分（40%）去磷酸化的全酪蛋白在不同磷酸化水平下，αs1-酪蛋白和β-酪蛋白呈现多条条带。观察到β-乳球蛋白A和B、αs1-酪蛋白A、B和C以及β-酪蛋白A、B和C的遗传表型分离。从不同类型奶酪中提取的乳蛋白的电泳图谱各不相同。我们改良的方法为研究人员提供了一种快速技术，可根据酪蛋白和乳清蛋白的电荷质量比在同一尿素凝胶上进行分离。
