Electron loss from multiply protonated lysozyme ions in high energy collisions with molecular oxygen

We report on the electron loss from multiply protonated lysozyme ions Lys-H -n(n+) {n = 7 - 17) and the concomitant formation of Lys-Hn((n+1)+.) in hig h-energy collisions with molecular oxygen (laboratory kinetic energy = 50 x n keV). The cross section for electron loss increases with the charge stat e of the precursor from n = 7 to n = 11 and then remains constant when n in creases further. The absolute size of the cross section ranges from 100 to 200 Angstrom (2). The electron loss is modeled as an electron transfer proc ess between lysozyme canons and molecular oxygen. (C) 2001 American Society for Mass Spectrometry.