Proteomic analysis: why and how?

The proteome, first formalized in 1995, designs all the proteins expressed by the genome of a cell, tissu, or organ at a defined time. Proteomic analy sis leads to a description of the regulation of gene expression by the stud y of proteins and of their posttranslational modifications. Proteomic analy sis is based on three technologies: 1) Two-dimensional electrophoresis allo wing the separation of thousands of proteins from a single mixture; 2) mass spectrometry allowing the characterization of picoquantities of polypeptid es and providing data on post-translational modifications; 3) Bioinformatic which is required for the quantification of protein level and for the cons titution of databases of protein expression profiles, Complementing the met hods of the genomics, the use of proteomic analysis is widely spreading in the fields of fundamental biology, biomedicine and pharmacology for the ide ntification of new biological markers and therapeutic targets.