ISSN:
0030-493X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Ionspray ionization of solutions containing peptides (M) plus alkali metal ions X+ produces [M + X]+, [M + H + X]2+ and [M + 2X]2+ ions. Low-energy collision-induced dissociation of these species demonstrated a marked trend towards decreased strength of the M-X+ interaction with increasing size of X+. For example, the [M +2X]2+ species yield predominantly [M + X]+ plus X+ for X+ = K+, Rb+, Cs+, but rich spectra of fragment ions incorporating X+ when X+ = Li+ or Na+. In general, these fragmentation reactions correspond to those established previously for the corresponding [M + X]+ precursor, including formation of [bi + X + OH]+ and [bi + X - H]+ fragments. As a special case, complexes of Li+ or Na+ with peptides having Arg (but not Lys or other basic residues) at the C-terminus undergo a facile loss of 60 u. The resulting [M + X - 60]+ ions also fragment further to yield [yi′ + X - 60]+ fragments. Characterization of the 60 u neutral loss was undertaken by using tandem mass spectrometry plus hydrogen-deuterium exchange, and a mechanism is proposed to account for the characteristics of the process.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/oms.1210281012
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