Characterization of native multicomponent protein mixtures by one- and two-dimensional gradient electrophoresis

An arrangement of one- and two-dimensional polyacrylamide gradients has been applied to the analysis of multicomponent mixtures of soluble proteins: (1) two-dimensional 3-25% slabs; (2) 3-40% cylinders; and (3) 20-50% cylinders. The run in the first dimension is performed in non-restrictive agarose gel to ascertain a "pure" charge abscissa. Gradient electrophoresis is performed over prolonged periods in order to reach or closely approach the exclusion (pore) limit, which is taken as an operational parameter for the hydrodynamic size of globular molecules irrespective of their frictional ratios. For each of the three gradients one to four reference mixtures were formulated that allow size evaluations of non-denatured proteins. Human serum again proved its usefulness as a universal reference mixture for newly developed techniques. The number of stainable components is in accordance with expectation based on the broad knowledge of serum proteins. Two-dimensional agarose/gradient electrophoresis seems to fulfil the one band-one protein strategy of high-resolution techniques.