title: Sensitive detection of phosphopeptides by matrix-assisted laser desorption/ionization mass spectrometry: use of alkylphosphonic acids as matrix additives.
abstract: Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been one of the most powerful tools for analyzing protein phosphorylation. However, it is frequently difficult to detect phosphopeptides with high sensitivity by MALDI-MS. In our investigation of matrix/matrix-additive substances for improving the phosphopeptide ion response in MALDI-MS, we found that the addition of low-concentration alkylphosphonic acid to the matrix/analyte solution significantly enhanced the signal of phosphopeptides. In this study, the combination of methanediphosphonic acid and 2,5-dihydroxybenzoic acid gave the best results. In addition to enhancing the signal of the phosphopeptides, alkylphosphonic acid almost completely eliminated the signals of sodium and potassium ion adducts. We report herein sensitive detection of phosphopeptides by MALDI-MS with the use of alkylphosphonic acids as matrix additives.
authors.affiliation: Institute for Protein Research, Osaka University, Suita, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kuyama
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sonomura
authors.forename: Osamu
authors.initials: O
authors.lastname: Nishimura
mesh_terms: D000818:Animals; D004164:Diphosphonates / Q000737:chemistry*; D005841:Gentisates / Q000737:chemistry*; D007202:Indicators and Reagents; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000737:chemistry*; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D004164:Diphosphonates; D005841:Gentisates; D007202:Indicators and Reagents; D010748:Phosphopeptides; C027474:methylene diphosphonate; C010925:2,5-dihydroxybenzoic acid