title: Investigation of intramolecular proton migration in a series of model, metal-cationized tripeptides using in situ generation of an isotope label.
abstract: In this study we used an isotope label, generated in situ, to investigate intramolecular proton migration or scrambling during formation of [b(2)+17+Li](+) products by collision-induced dissociation (CID) of Li(+)-cationized tripeptides. To generate the isotope label, we used a McLafferty-type rearrangement of N-terminally acetylated, C-terminal peptide tert-butyl esters in which all amide positions were exchanged with deuterium. Using a set of small, model peptides, we show that intramolecular proton scrambling occurs during CID, particularly amongst adjacent sites along a peptide backbone, on the time scales employed for low-energy collisional activation in an ion-trap mass spectrometer.
authors.affiliation: Department of Chemistry, Wichita State University, Wichita, KS 67260-0051, USA.
authors.forename: Kellis
authors.initials: K
authors.lastname: Bulleigh
authors.forename: Angela
authors.initials: A
authors.lastname: Howard
authors.forename: Trang
authors.initials: T
authors.lastname: Do
authors.forename: Qun
authors.initials: Q
authors.lastname: Wu
authors.forename: Victor
authors.initials: V
authors.lastname: Anbalagan
authors.forename: Michael Van
authors.initials: MV
authors.lastname: Stipdonk
mesh_terms: D002412:Cations; D003903:Deuterium; D007553:Isotope Labeling / Q000379:methods*; D008094:Lithium / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D008670:Metals / Q000737:chemistry; D009038:Motion; D010455:Peptides / Q000032:analysis* / Q000737:chemistry*; D011522:Protons
chemical_list: D002412:Cations; D008670:Metals; D010455:Peptides; D011522:Protons; D008094:Lithium; D003903:Deuterium