Effect of the Addition of Diammonium Citrate to α-Cyano-4-Hydroxycinnamic Acid (CHCA) Matrix for the Detection of Phosphorylated Peptide in Phosphorylation Reactions Using Cell and Tissue Lysates

Jeong Hun Kang, Riki Toita, Jun Oishi, Takuro Niidome, Yoshiki Katayama

Research output: Contribution to journalArticle

15 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)1925-1931
Number of pages7
JournalJournal of the American Society for Mass Spectrometry
Issue number11
Publication statusPublished - Nov 1 2007


All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Spectroscopy

Cite this