The ionization of phosphorylated peptides is usually suppressed by non-phosphorylated peptides when α-cyano-4-hydroxycinnamic acid (CHCA) is used as a matrix for matrix-assisted laser desorption/ionization-time-of-Flight (MALDI-TOF) mass spectrometry analysis. In the present study, we examined the effect of diammonium citrate addition to the CHCA matrix on the detection of phosphorylated peptides. Substrates for protein kinase C (PKC) and c-Src were synthesized and phosphorylated by reaction with cell and tissue lysate samples. The addition of diammonium citrate to the CHCA matrix increased the sensitivity for distinguishing phosphorylated peptides from background noise. However, the effect depended on substrate concentration.
|Number of pages||7|
|Journal||Journal of the American Society for Mass Spectrometry|
|Publication status||Published - Nov 1 2007|
All Science Journal Classification (ASJC) codes
- Structural Biology