Flattening, shifting and comparing pH gradients in slab gel electrofocusing by local increases of gel volume

Abstract

Abstract A simple and versatile technique of horizontal slab gel electrofocusing is described which is based on a discontinuity of the gel volume along the pH axis achieved by overlaying ampholyte containing gel strips, of a defined volume and shape, at various locations on a base gel during the prerun of isoelectric focusing. In the electric field the overlaid gel strip delivers ampholytes of a distinct pI interval into the strip‐free part of the base gel and removes from the latter some ampholytes present in the system. Flattening of the pH gradient in the strip‐free part of the gel is the consequence. The technique is especially useful for thin gels and can be performed with any commercially available horizontal slab apparatus.