Enhanced detection of phosphopeptides in matrix-assisted laser desorption/ionization mass spectrometry using ammonium salts.
J Am Soc Mass Spectrom
; 10(1): 35-44, 1999 Jan.
Article
em En
| MEDLINE
| ID: mdl-9888183
ABSTRACT
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) has been used successfully to detect phosphorylation sites in proteins. Applications may be limited by the low response of phosphopeptides compared to nonphosphorylated peptides in MALDI MS. The addition of ammonium salts to the matrix/analyte solution substantially enhances the signal for phosphopeptides. In examples shown for equimolar mixtures, the phosphorylated peptide peaks become the largest peaks in the spectrum upon ammonium ion addition. This can allow for the identification of phosphopeptides in an unfractionated proteolytic digestion mixture. Sufficient numbers of protonated phosphopeptides can be generated such that they can be subjected to postsource decay analysis, in order to confirm the number of phosphate groups present. The approach works well with the common MALDI matrices such as alpha-cyano-4-hydroxycinnamic acid and 2,5-dihydroxybenzoic acid, and with ammonium salts such as diammonium citrate and ammonium acetate.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfopeptídeos
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
J Am Soc Mass Spectrom
Ano de publicação:
1999
Tipo de documento:
Article