Two dimensional electrophoresis method for additional characterization of paraproteins in serum. Clinical application...

High resolution two dimensional electrophoresis, one of the most potent methods for the analytical separation of proteins, is still used only in specialized laboratories. The present paper describes a two dimensional electrophoresis method, which permits characterization of abnormal serum proteins (paraproteins) and is suitable for application in a clinical laboratory. Both steps of the electrophoresis are performed by the "flat bed technique". The critical transfer from the isoelectric focusing step to the gel of the second dimension is facilitated by use of specially prepared foil stencils. The practicality of the procedure was considerably increased by using commercially available materials such as gels for isoelectric focusing and the silver stain kit. The analysis can be calibrated by measurement of the pH gradient and by using molecular weight protein standards. Moreover, two different samples can be analysed simultaneously in the same gels of the first and the second dimension. This permits a direct comparison of the sample of interest with the sample of reference. Serum samples showing an abnormal band ("M gradient") in routine methods such as agarose gel electrophoresis, were analysed by the described method. Some "M gradients" consisted of single abnormal proteins. Another sample showed a "M gradient" composed of a number of abnormal protein spots in our method. Questions concerning pathobiological and clinical evaluation of the findings justify further studies using this method.