Protéomique et spectrométrie de masse

Proteomics is the study of the bulk of proteins in a cell, a tissue or a biological fluid. The study can be focused on proteins differentially expressed in function of the physiological or pathological state. Most methods for proteomic studies are explained in this paper, particularly the classical approach using two-dimensional gel electrophoresis (2-DGE), for separating proteins, coupled to mass spectrometry for protein identification. Other approaches combine principles for the separation of proteins or peptides using chromatography, or with the use of isotopic labelling for quantitative analysis. Some examples are given from our experience or from literature; they regard the search of new biochemical markers of diseases or of putative targets for conceiving new drugs, for example in cancer area with studies on tumours or cell lines, or moreover directly on biological fluids, such as plasma or urines… New markers for diagnosis or prognosis have already been proposed; some of them are in a validation phase or have to be confirmed by pathologic anatomy. Studies on plasma or serum often are difficult because of major proteins needing partial depletion or pre-fractionation. Otherwise, the direct analysis of plasma by 2-DGE allows the phenotyping of both α1-antitrypsin and haptoglobin, also the study of variants of glycosylation. After the era of “only genomics”, we can assume that proteomics will lead to a better knowledge of diseases, to their more complete phenotypic characterization, to the development of new strategies for diagnosis and to the emergence of new approaches for therapy.