Oligopeptide fragmentation viewed as constant neutral loss.pdfVIP

Oligopeptide Fragmentation Viewed as Constant Neutral Loss* C. Fenselau and C. M. Murphy Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland, USA R. J. Cotter Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, Maryland, USA Spectra were recorded of all fragment ions formed by elimination of 28-u neutral fragments in fast atom bombardment spectra of peptides in the mass range 1000-1800 u. This approach can provide less complex spectra than either conventionally scanned spectra or product ion scans from collisionally activated four-sector experiments, and spectra that contain infor- mation that is both overlapping and complementary to those from the other techniques. Constant neutral loss spectra may provide a reading frame for distinguishing sequence ion series in tandem or single analyzer spectra. (J Am See Muss Spectrom 1990, 1, 336-340) e observation of decompositions defined by ety of structures. The loss of 28 u is monitored on a constancy in the mass of the neutral fragment double-focusing mass spectrometer using the scan law T [l-3] has allowed mechanism-based enhance- B2(1 - E)/E2 = constant. ment of both signal-to-noise (SIN) ratios and speci- ficity for characterizing targeted analytes in complex matrices. Working with tripeptides and tetrapeptides, Experimental dePauw et al. [4] suggested that the constant neutral