The current state of the art in high-resolution two-dimensional electrophoresis

The study of the "proteomes" of human cells, tissues, and body fluids is a big challenge, and several highly sophisticated workflow approaches are pursued to achieve as comprehensive information as possible. Initially proteome analysis was exclusively based on the gel-based workflow, employing two-dimensional electrophoresis of protein extracts followed by mass spectrometry of the tryptic peptide digests of protein spots. Meanwhile several additional proteomics workflows are applied, which are mostly based on separation and analysis of tryptic peptides without separating the protein mixture. However, direct information on quantitative and qualitative changes of protein expressions can only be obtained by methods operating on the protein level, no other method can replace two-dimensional electrophoresis. In this review we compile the different techniques of high-resolution two-dimensional electrophoresis and their further developments to increase the degree of reliance of the method.