LC-MS/MS analyses require prior sample processing. The methods applied are adapted according to the sample in order to make it compatible with the LC-MS / MS analysis and to maximize the number of proteins to be identified.
Sample processing methods
- Precipitation / proteins concentration
- Enzymatic digestion (Trypsic and/or C Lysin)
- Peptide desalting by StageTips
- Pre-fractionation: When samples are very complex, it is preferable to perform a prefractionation step in order to identify more proteins. We perform mass pre-fractionation using SDS-PAGE gel. It is also possible to perform prefractionation by charge or polarity.
- Removal of abundant proteins: the presence of predominant proteins in a sample may be a handicap for the study and the identification of less abundant proteins. When necessary, we use the ProteoMiner system (Bio-Rad) to reduce the abundance of major proteins.
In practice: don’t hesitate to contact us to learn more at medecine-p3s@sorbonne-universite.fr or at 01.40.77.81.32