Protocols for sample preparation

For most protein and proteome analyses sample purification is one of the most crucial steps to achieve successful mass spectrometric data. Various sample impurities interfere with the ionization process or result in strong signals and therefore significantly drop the sensitivity of the mass spectrometric analysis. One of the most frequently used protein purification method is gel electrophoresis which is fully compatible with downstream mass spectrometry. Proteins separated and purified by gel electrophoresis are in gel digested with trypsin and the resulting tryptic peptides eluted from the gel. The peptides can be further purified by ZipTip-extraction or directly analysed by MALDI or ESI-coupled mass spectrometry.

Alternatively proteins or peptides can be purified by reversed phase chromatography or another suitable chromatography such as ion exchange chromatography followed by a solid phase extraction to remove salts and other hydrophilic impurities. Proteins can then be digested in solution containing up to 80% acetonitrile.

Please enquire for further details and to determine a suitable cleanup procedure for your individual sample(s).

Protocols

Tryptic digestion in-gel

Tryptic digestion in-solution

ZipTip-extraction

Guanidination and sulfonation for de novo sequencing by mass spectrometry