title: Characterization of peptides by liquid chromatography/electrospray ionization mass spectrometry using silver nitrate as a post-column complexant.
abstract: Two model peptides, des-Arg1-bradykinin (DAB) and bradykinin (B), were cationized by Ag+ after their separation by reversed-phase liquid chromatography (RPLC) prior to mass spectrometry (MS). Silver nitrate solution was used as a post-column reagent. The RPLC and MS experimental conditions were optimized using flow injection in order to obtain sufficiently abundant silver adducts to permit MS/MS experiments. The use of water-methanol with 0.1% formic acid as mobile phase allowed a good chromatographic separation of the two peptides with a polymeric stationary phase and sufficiently abundant silver-containing adducts, [M + Ag + H]2+ and [M + 2Ag]2+. The gas-phase dissociation of [DAB + Ag + H]2+ and [DAB + 2Ag]2+ led to interpretable mass spectra during the on-line cationization experiment. Most of the ions obtained by dissociating [DAB + Ag + H]2+ and [DAB + 2Ag]2+ species are silver-containing ions but the ions produced depend on the parent. The ions coming from the dissociation of the doubly charged silver adducts [DAB + Ag + H]2+ or [DAB + 2Ag]2+ are of interest compared with those coming from the singly charged silver species or doubly charged protonated species. The fragmentation of the doubly charged silver adducts provides ions over the entire mass range. Although the presence of several prolines in des-Arg1-bradykinin prevents the formation of some expected ions, the observation of triplets [an-H + Ag]+, [bn-H + Ag]+ and [bn + OH + Ag]+ produced by the dissociation of on-line Ag(+)-cationized peptides could contribute to greater success of automatic sequencing of peptides.
authors.affiliation: Laboratoire Analyse et Environnement, Université d'Evry Val d'Essonne, CNRS UMR 8587, Boulevard François Mitterrand, 91025 Evry, France.
authors.forename: Ghislain
authors.initials: G
authors.lastname: Cheguillaume
authors.forename: William
authors.initials: W
authors.lastname: Buchmann
authors.forename: Bernard
authors.initials: B
authors.lastname: Desmazières
authors.forename: Jeanine
authors.initials: J
authors.lastname: Tortajada
mesh_terms: D001920:Bradykinin / Q000032:analysis* / Q000737:chemistry*; D002413:Cations, Divalent / Q000737:chemistry; D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D008958:Models, Molecular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012835:Silver Nitrate / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D002413:Cations, Divalent; D012997:Solvents; D012835:Silver Nitrate; D001920:Bradykinin