Two-Dimensional Electrophoresis

Abstract

In organelles, cells and tissues of all organisms complex functions and metabolic reactions are maintained by proteins within and at the surface of each compartment. The number of proteins occurring in a biological compartment corresponds to the complexity of the functions it has to fulfill. Ribosomes, as relatively high specialized compartments, contain in the case of E.coli 54 different proteins, whereas estimations for the number of expressed genes in a typical human cell are in the range of about 5000. The human genome contains about 50 000–100 000 genes. For the registration and characterization of the components of these complex systems high resolution methods are necessary. Characterization of all components of a biological compartment - the ribosomes - became a reality when methods became available for the resolution of about 50 different proteins. These methods were: first, two-dimensional electrophoresis (2-DE) (Kaltschmidt and Wittmann 1970) and, later, HPLC (Kamp and Wittmann-Liebold 1984). Today, improved 2-DE techniques play an important role in investigating the functional part of genes, i.e., proteins, within the human genome project. Furthermore changes in protein composition may be elucidated by subtractive analyses of different biological situations, for example, in disease or during differentiation.