title: Identification of isoenzymes using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
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.
authors.affiliation: Laboratoire de Spectrométrie de Masse Bio-Organique, CNRS-UMR 6014, UFR des Sciences, Université de Rouen, 76 821 Mont-Saint-Aignan Cedex, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Hardouin
authors.forename: Marie
authors.initials: M
authors.lastname: Hubert-Roux
authors.forename: Agnès F
authors.initials: AF
authors.lastname: Delmas
authors.forename: Catherine
authors.initials: C
authors.lastname: Lange
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D005982:Glutathione Transferase / Q000737:chemistry*; D007527:Isoenzymes / Q000737:chemistry*; D008969:Molecular Sequence Data; D040901:Proteomics; D020539:Sequence Analysis, Protein / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013552:Swine
chemical_list: D007527:Isoenzymes; D005982:Glutathione Transferase