A. Sarver et al., Analysis of peptides and proteins containing nitrotyrosine by matrix-assisted laser desorption/ionization mass spectrometry, J AM SOC M, 12(4), 2001, pp. 439-448
Citations number
40
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
Oxidative damage to proteins can occur under physiological conditions throu
gh the action of reactive oxygen species, including those containing nitrog
en such as peroxynitrite (ONO2-). Peroxynitrite has been shown in vitro to
target tyrosine residues in proteins through free radical addition to produ
ce S-nitrotyrosine. In this work, we show that mass spectral patterns assoc
iated with 3-nitrotyrosine containing peptides allow identification of pept
ides containing this modification. Matrix-assisted laser desorption/ionizat
ion (MALDI) mass spectrometry was used to characterize a synthetic peptide
AAFGY(m-NO2)AR and several peptides containing S-nitrotyrosine derived from
bovine serum albumin treated with tetranitromethane. A unique series of io
ns were found for these peptides in addition to the mass shift of +45 Da co
rresponding to the addition of the nitro group. Specifically, two additiona
l ions were observed at roughly equal abundance that correspond to the loss
of one and two oxygens, and at lower abundances, two ions are seen that su
ggest the formation of hydroxylamine and amine derivatives. These latter fo
ur components appear to originate by laser-induced photochemical decomposit
ion. MALDI-MS analysis of the synthetic peptide containing 3-nitrotyrosine
revealed this same pattern. Post-source decay (PSD) MALDI-time-of-flight (T
OF) and collisional activation using a prototype MALDI quadrupole TOF yield
ed extensive fragmentation that allowed site-specific identification of S-n
itrotyrosine. Conversion of peptides containing 3-nitrotyrosine to 3-aminot
yrosine with Na2S2O4 yielded a single molecular ion by MALDI with an abunda
nt sidechain loss under PSD conditions. These observations suggest that MAL
DI can provide a selective method for the analysis and characterization of
3-nitrotyrosine-containing peptides. (C) 2001 American Society for Mass Spe
ctrometry.