Step-by-step preparation of proteins for mass spectrometric analysis

Nowadays, identification of proteins from biological samples by mass spectrometry is widely used. In principle there are two scenarios. Proteins are pre-fractionated in some way, e.g. by gel electrophoresis or are analyzed as complex mixture (shot gun). Shot gun proteomics became recently more popular, because of technological developments on the mass spectrometer side which allows now the identification of several thousand proteins from complex biological matrix. However, in many cases it is still useful to separate proteins first in a gel. But not only mass spectrometer technology made progress. This is also true for the sample preparation. Recently, protocols and techniques were developed which make the analysis of starting material in the low microgram range possible and also simplify the whole procedure. Detailed protocols will be described allowing also inexperienced beginners to get good results.