Mass Spectrometry of Biomolecules

Mass Spectrometry of Biomolecules

Mass spectrometers used for the analysis of macromolecules from biological sources, such as proteins, peptides, DNA or RNA oligomers, have experienced tremendious improvements in recent years. Electro spray ionization mass spectrometry (ESI-MS) and matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) have become the methods of choice. Both techniques are powerful analytical tools by themself, but are most powerful if used in combination with techniques such as gel electrophoresis, electroblotting, LC, CE or protein sequencing. This is the major technology used for proteomic approaches.

Mass Spectrometer

All mass spectrometers designed to analyze proteins consist of two essential components, the ion source and the mass analyzer. In the ion source, a seemingly unlikely phase transition is effected: proteins introduced as solids or in solution are converted into intact, naked ionized molecules in the gas phase. Subsequently, in the mass analyzer, the mass-to-charge (m/z) ratios of the naked protein molecule ions are determined.

Protein Analysis

The determination of the carbohydrate portion of glycoproteins provides an analytical challenge to researchers, especially when only small amounts of sample are available. The reason for this is the very large number of isomers that are possible when these structures are built up from their constituent monosaccharides. Phosphoproteins play a central role in many intracellular processes, including signal transduction and regulation of cell division. The site and extent of phosphorylation of key proteins are believed to play an important regulatory role in many intracellular signaling pathways.