title: Collisionally activated decomposition of modified peptides using a tandem hybrid instrument.
abstract: Analyses are described of small peptides and related compounds using a tandem hybrid mass spectrometer of BEQQ geometry. Collisionally activated decomposition of [M + H]+ ions, generated by fast atom bombardment, was performed in the radio frequency (rf)-only quadrupole. Interpretation of fragmentation was greatly facilitated by analysis of labeled analogs, obtained by 18O exchange of carboxyl oxygens. N-Acetylation was also valuable although significant changes in fragmentation resulted from derivatization. Daughter ion spectra of [M + H]+ ions of angiotensin III showed diagnostic fragmentations throughout the peptide chain.
authors.affiliation: Center for Experimental Therapeutics, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: S J
authors.initials: SJ
authors.lastname: Gaskell
authors.forename: P E
authors.initials: PE
authors.lastname: Haroldsen
authors.forename: M H
authors.initials: MH
authors.lastname: Reilly
mesh_terms: D000805:Angiotensin III / Q000032:analysis; D013058:Mass Spectrometry; D010455:Peptides / Q000032:analysis*
chemical_list: D010455:Peptides; D000805:Angiotensin III