ELECTROSPRAY-IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY IN PROTEIN CHEMISTRY

A novel electrospray ionization time-of-flight mass spectrometer with an ion mirror has been developed. The ''orthogonal acceleration'' of ions combined with ion storage modulation enables large sensitivity to be obtained with moderate (R > 2000) mass resolution. Application of the transient recording system allows simultaneous registration of ions of all masses, with sensitivity equal to that in the single ion monitoring regime. The potential of this technique is demonstrated by the primary structure determination of cationic peptides from porcine neutrophils and by the study of the pathways of recombinant proinsulin proteolytic processing catalyzed by various trypsin forms.