Speaker: Piotr Stefanowicz
Title: Derivatization with ionization tags in peptide analysis by mass spectrometry
Mass spectrometry is a specific and sensitive method of proteome analysis. One of the crucial parameter influencing the response factor in the ESI positive mode is proton affinity, hence the signal abundance depends on the peptide sequence as well as matrix effects. Derivatization of peptides, which results in introduction of a fixed charge is one of ways to overcome the sensitivity problem in peptide analysis. Thus, several strategies like e.g. incorporation of quaternary ammonium or phosponium moiety leading to formation of charge-tagged peptides have been developed. Recently we developed new ionization markers based on 2,4,6-triphenylpyridinium and 2,4,6-trimethylpyridinium salts. Using of inexpensive and commercially available pyrylium salt allows selective derivatization of primary amino groups, especially those sterically unhindered, such as ε-amino group of lysine. The 2,4,6-triphenylpyridinium modified peptides generate in MS/MS experiments an abundant protonated 2,4,6-triphenylpyridinium ion. This fragment is a promising reporter ion for the multiple reactions monitoring (MRM) analysis. In addition, the fixed positive charge of the pyridinium group enhances the ionization efficiency. Other advantages of the proposed ionization enhancers are the simplicity of derivatization of peptides and the possibility of convenient incorporation of isotopic labels into derivatized peptides.
Piotr Stefanowicz from the University of Wrocław, is visiting Einar and Kacper in Oslo.
The Hylleraas seminars alternate between Oslo (room V205) and Tromsø (room C302), and are broadcasted by video conference to the other place. It is possible to follow the seminars externally upon request.