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Matrix-assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) Mass Spectrometric Analysis of Intact Proteins Larger than 100 kDa
Published on: September 9, 2013
Identification of isoenzymes using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
Julie Hardouin1, Marie Hubert-Roux, Agnès F Delmas
1Laboratoire de Spectrométrie de Masse Bio-Organique, CNRS-UMR 6014, UFR des Sciences, Université de Rouen, 76 821 Mont-Saint-Aignan Cedex, France.
Abstract:
The identification of isoforms is one of the great challenges in proteomics due to the large number of identical amino acids preventing their separations by two-dimensional electrophoresis. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has become a rapid and sensitive tool in proteomics, notably with the new instrumental improvements. In this study, we used several acquisition modes of MALDI-TOFMS to identify isoforms of porcine glutathiones S-transferase. The use of multiple proteases coupled to the different acquisition modes of MALDI-TOFMS (linear, reflectron, post-source decay (PSD) and in-source decay, positive and negative modes) allowed the identification of two sequences. Moreover, a third sequence is pointed out from a PSD study of a tryptic ion revealing the modification of the amino acid tyrosine 146 to phenylalanine.
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