Mass Spectrometry determination of the phosphorylation sites of the four Serine/Threonine Protein Kinases and the substrate MurC from Corynebacterium glutamicum.

摘要

Mass spectrometry profiling coupled to in vitro kinase assays unambiguously demonstrated the Ser/thr kinase activity of the four Corynebacterium glutamicum kinases (PknA, PkNB, PknG and PknL) and the phosphorylation sites of the MurC substrate of PknA. CAD and ETE MS/MS analyses are very complementary for peptides phosphorylation sites determination. However, classical tryptic peptides are not good candidates for ETD MS/MS, to be efficient this technique needs lysine (or arginine) rich peptides. The use of an other enzyme digest than trypsin is preferable (protease Glu-C for instance).