Nowadays, investigators in all fields are faced with the identificatio
n of unknown, up- or down-regulated, modified proteins that they are t
rying to identify. Two-dimensional (2-D) gel electrophoresis, with its
ability to resolve several thousand proteins, is an extremely powerfu
l technique. The current resolution and reproducibility of 2-D gel tec
hnology and the establishment of computer assisted 2-D gel protein dat
abases have paved new ways for the identification of proteins.