Development of a derivatisation method for the analysis of aldehyde modified amino acid residues in proteins by Fourier transform mass spectrometry

Development of an on-line weak-cation exchange liquid chromatography–tandem mass spectrometric method for screening aldehyde products in biological matrices

“…The concentration of MDA, hexanal, butanal, 4-HHE and 4-HNE increased with time, whereas the concentration of pentanal, heptanal, octanal and decanal first increase but decline after 3.5 h. This may indicate additional reactions of the aldehydic products, such as peroxyaldehydes, as have been reported by Brash et al [31]. Another possible explanation could be that the aldehydes react slowly in time with proteins via an imine formation with lysine [37].…”

Mass Spectrometric Evidence for the Existence of Distinct Modifications of Different Proteins by 2(E),4(E)-Decadienal

“…It is well known that the peptides containing a fixed positive charge are extremely sensitive to MALDI-TOF-MS − . Various Lys pyridinium adducts involving two or more alkenal molecules have been detected and characterized by MS and/or NMR upon incubation of alkenals with a model peptide or a protein − . DDE belongs to the alkenal class, but with one more conjugated double bonds.…”

“…The extraordinary sensitivity to MALDI-TOF-MS of these modified peptides implicates the formation of the pyridinium derivative, which has a fixed positive charge. On the basis of the pyridinium product formed between alkenals and Lys ,, , the proposed structures 1a and 1b of these DDE adducts as well as their formation mechanism are shown in Scheme . These two isomeric adducts were both detected in the LC-MS.…”

“…Additional chemical evidence that suggests the presence of the pyridinium moiety came from the reduction by sodium borohydride (40), which results in an additional mass increment of 3 Da (Table 2) and a dramatically reduced intensity in the MALDI-TOF mass spectra. The reduction of pyridinium 1a (M+268) by NaBH 4 leads to the intermediate dihydropyridinium 2 (M+269) (Scheme 2).…”

Influence of pH, Temperature, and Water Activity on Covalent Adduct Formation between Selected Flavor Compounds and Model Protein β-Lactoglobulin

“…The +268 adduct could be two Schiff base adducts that have been formed with multiple lysine groups present or the pyridinium adduct that is formed with a single lysine group and two citral molecules (Figure ). Various lysine pyridinium adducts involving two or more alkenal molecules have been shown in previous studies using MS and/or NMR spectroscopy and model protein/peptides. − The reaction mechanism is shown in Figure . The +402 and +554 adducts correspond to the additional Schiff base and Michael adducts at the other reactive sites (e.g., lysine and arginine).…”