title: Tryptic y(++) fragment ion distributions are guided by Coulombic repulsion.
abstract: Ideal tryptic peptides contain only a single basic residue, located at the C-terminus. Collisional fragmentation of their doubly- or triply-protonated ions generates doubly-charged y(++) fragment ions with modest intensities. The size distribution of the y(++) fragments, when averaged over many spectra, corresponds closely to the expectations from charge-directed backbone cleavage and a Coulomb-Boltzmann distribution of mobile protons. This observation should be helpful in developing mechanistic models for y(++) formation.
authors.affiliation: Chemical and Biochemical Reference Data Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. karl.irikura@nist.gov
authors.forename: Karl K
authors.initials: KK
authors.lastname: Irikura
authors.forename: John K
authors.initials: JK
authors.lastname: Merle
authors.forename: Yamil
authors.initials: Y
authors.lastname: Simón-Manso
mesh_terms: D013058:Mass Spectrometry; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry*; D011522:Protons; D055672:Static Electricity; D014357:Trypsin / Q000737:chemistry*
chemical_list: D010446:Peptide Fragments; D011522:Protons; D014357:Trypsin