title: Accurate peptide sequencing by post-source decay matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
abstract: Partial 18O-labeling of peptides has been applied to post-source decay experiments in a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. The ions which originate from the carboxyl terminus of a peptide partially retain 18O atoms which have readily been incorporated into the C-terminal carboxyl groups during enzymatic hydrolysis in a buffer containing 40 atom percent H218O. The isotopic resolution of singly charged precursor ions and their product ions obtained for peptides up to ca. 2800 Da has been achieved using the delayed extraction method, which permits the rapid identification and assignment of the 18O-labeled and non-labeled ion species in the PSD spectra. The results obtained from several 18O-labeled peptides, derived from an enzymatic digest, demonstrate the accuracy and reproducibility of the present method, which will be in widespread use for protein identification via database searching or for investigations of totally unknown proteins.
authors.affiliation: Institute for Protein Research, Osaka University, Japan.
authors.forename: W
authors.initials: W
authors.lastname: Mo
authors.forename: T
authors.initials: T
authors.lastname: Takao
authors.forename: Y
authors.initials: Y
authors.lastname: Shimonishi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D006736:Horses; D008969:Molecular Sequence Data; D009211:Myoglobin / Q000032:analysis; D010455:Peptides / Q000032:analysis*; D017421:Sequence Analysis / Q000295:instrumentation / Q000379:methods*; D012697:Serine Endopeptidases / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D009211:Myoglobin; D010455:Peptides; D012697:Serine Endopeptidases; C036813:lysyl endopeptidase