A method for density gradient isoelectric focusing in small scale

A method for density gradient isoelectric focusing in small seale is described. It utilizes the same equipment as that ordinarily used for electrofocusing in polyacrylamide gels, thus allowing several samples to be analyzed in the same experiment and the simultaneous electrofocusing in density gradients and gels. Data concerning the stability of the pH gradient and the effect of salt and sample load on the focusing are given. Three different methods for fractionating the gradient are described; in one of these the frozen gradient is sliced with an ordinary gel alicer. This fractionation method is especially advantageous if the gradient contains zones of highly aggregated material, and it also allows the gradients to be stored frozen for later fractionation.