Matrix-assisted laser post source decay studies

Experimentation showed that the protein was not glycosylated and that the sequence at the iV-amino acid terminus corresponded to that expected. The C-terminus sequence, however, did not correspond to that predicted and these data were interpreted in terms of the presence of a heterogeneous, truncated, protein. A study of the tryptic digest fragments from this protein with matrix-assisted laser desorption ionization (MALDI) with post-source decay enabled the authors to suggest the positions at which the parent protein had been truncated. 

Several original papers must be mentioned that deal with mass spectrometric techniques which the numerous reviews do not comprise. Kaufmann and coworkers268,288 studied the mass spectrometric analysis of carotenoids and some of their fatty acid esters using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry and its post-source-decay (PSD) variant. Some advantages concerning the thermal instability and limited solubility were discussed, but the fragmentation paths of the carotenoid cations were found to be essentially the same as those observed with conventional techniques. 

Keki, S., Deak, G., and Zsuga, M., Fragmentation study of rutin, a naturally occurring flavone glycoside cationized with different alkali metal ions, using post-source decay matrix-assisted laser desorption/ionization mass spectrometry, J. Mass Spectrom., 36, 1312, 2001. 

In this study, we used matrix-assisted laser desorption ionization /Mass Spectrometry (MALDI/MS) to identify the peptides released from gastric parietal cell microsomes. MALDI, because of its sensitivity and relative tolerance to the presence of salts and buffers was examined for the analysis of unfractionated proteolytic digests (9, 10). MALDI with post-source decay (PSD) analysis was used to obtain sequence information on peptides even in crude digestion mixtures. Our strategy (Figure 1) consisted of proteolysis of intact vesicles, centrifugation at high speeds to separate membrane bound and soluble fractions and analysis of the mixture of released peptides by MALDI/MS. In addition, to increase the... 

S. Metzer and R. Hoffmann, Studies on dephosphorylation of phosphotyrosine-containing peptides during post-source decay in matrix-assisted laser desorption/ion-ization, 7. Mass Spectrom. 35, 1165-1177 (2000). 

A comparative study of in- and post-source decays of peptide and preformed ions in matrix-assisted laser desorption ionization time-of-flight mass spectrometry effective temperature and matrix effect./. Am. Soc. Mass Spectrom.,... 

J. C. (2002) Post-source decay time-of-flight study of fragmentation mechanisms of protonated synthetic polymers under matrix-assisted laser desorption/ionization conditions. Rapid Commun. Mass Spectrom., 16, 596-704. 

Lattova, E. Perreault, H. Krokmn, O. Matrix-assisted laser desorption/ionization tandem mass spectrometry and post-source decay fragmentation study of phenylhydrazones of N-linked oligosaccharides from ovalbumin. J. Am. Soc. Mass Spectrom. 2004, 15, 725-735. 

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