Current Gel Electrophoresis Approaches to Low-Abundance Protein Marker Discovery

Two-dimensional polyacrylamide gel electrophoresis (2-DE) is one of the oldest separation/analytical methods in biochemistry that became progressively the leading technology in proteomics. Over time it has steadily improved in sensitivity, reproducibility, and ease of manipulation. Today it remains irreplaceable in protein investigations. Although it is not the solution to all issues, it is of more interest when associated with complementary technologies capable of enhancing the detection of low-abundance species or expression modifications that intervene at the early stage of a given disease. This chapter describes 2-DE in association with a combinatorial peptide ligand library as an integrated tool to detect species that otherwise would remain undetectable.