title: Mass spectrometric characterization of phosphorylated peptides using MALDI in-source decay via redox reactions.
abstract: Matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) has been used for characterization of a phosphorylated peptides and proteins because labile phosphate group is not lost during the MALDI-ISD process. The conventional MALDI-ISD is initiated by the hydrogen transfer from reducing matrix molecules to peptide backbone, leading to c'- and z'-series ions. In contrast, when an oxidizing chemical 5-nitrosalicylic acid (5-NSA) is served as the MALDI-ISD matrix, a- and x-series ions are specifically generated by hydrogen abstraction from peptide backbone to matrix molecule. The 5-NSA provides useful complementary information to the conventional MALDI-ISD for the analysis of amino acid sequencing and site localization of phosphorylation in peptides. The MALDI-ISD with reducing and oxidizing matrix could be a useful method for the de novo peptide sequencing.
authors.affiliation: Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Asakawa
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Takayama
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives / Q000737:chemistry; D000595:Amino Acid Sequence; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010748:Phosphopeptides / Q000737:chemistry*; D010750:Phosphoproteins / Q000737:chemistry; D012459:Salicylates / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D010748:Phosphopeptides; D010750:Phosphoproteins; D012459:Salicylates; C510889:1,5-diaminonaphthalene; D015081:2-Naphthylamine