Production of polyacrylamide gradient gels for the electrophoretic resolution of lipoproteins

We describe a protocol to cast nondenaturing polyacrylamide gradient gels (SFBR3/31) for the size resolution of lipoproteins. The protocol yields gels with minimal lot-to-lot variation in length and electrophoretic properties. Absorbance profiles of cholesterol-stained lipoproteins in baboon sera were used to estimate the relative amounts of stain in four lipoprotein size classes (VLDL+LDL, HDL1, HDL2, and HDL3). When compared with gels from a commercial source, the SFBR3/31 gels gave very similar results in terms of precision (coefficients of variation) and of estimated amounts of lipoproteins in the four size classes. In other studies, we estimated peak diameters of protein-stained human lipoproteins after calibrating the gels with size standards. Peak diameters estimated using SFBR3/31 gels were highly correlated (r2 = 0.99, n = 33) with those estimated using gels from a commercial source. We conclude that the protocol reliably produces gradient gels that are suitable for the analysis of lipoprotein phenotypes.