Mass spectrometry: an essential tool for genome and proteome analysis

Mass spectrometry (MS), in its various forms, has become an essential tool for genome and proteome analysis. It involves gaseous ionization of the analyte to be examined, followed by separation of ions according to mass-to-charge (mlz) ratio and determination of molecular masses of iOIlSfrom mass spectra obtained after mass spectrometry of analyte. Several methods for ionization, mainly including MALDI and ES, each coupled with a specific mass spectral analysis system (e.g. TOF-MS and quadrupole MS) are available. MS/MS is devised particularly for the determination of amino acid sequences of small peptide. The advantage of MS over other techniques is its speed, since gel electrophoresis and labeling of the analyte, needed in other techniques used for genome/proteome analysis, can be dispensed with. Applications of mass spectrometry for genome analysis include DNA sequencing and SNP detection, the latter involving PinPoint assay (minisequencing), PNA hybridization, invader cleavage, "MALDI on a chip", etc. Similarly, its applications for proteome analysis include peptide sequencing, determination of molecular weights of proteins and protein identification by database search. Protein modifications and protein-protein interactions can also be examined by coupling mass spectrometry with database search. In this manner, mass spectrometry has become an essential tool for genome and proteome analysis