Gradient flattening of sodium dodecyl sulfate (SDS) and isoelectric focusing (IEF) gels

In addition to our previously reported versatile methods for sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis [1] and isoelectric focusing (IEF)-gel [2], I have achieved molecular weight gradient flattening of the SDS-polyacrylamide gel and pH gradient flattening of the IEF gel at any segment using the same electrophoresis system. Any crowded gel segment where congregated components are not separated well can easily be widened for good separation and any dispersed gel segment where components are too far apart can easily be narrowed. Therefore, every gel segment can be used effectively and meaningfully because the gradient curve can be adjusted to any distribution of the components. In the crowded area, any small spots of components which could not be detected previously because of nearby heavy staining or strong radioactivity of an abundant component can be sufficiently separated from the nearby spots in a small gel without sacrificing other areas.