STATISTICAL-ANALYSIS OF MASS-SPECTRAL DATA OBTAINED FROM SINGLY PROTONATED PEPTIDES UNDER HIGH-ENERGY COLLISION-INDUCED DISSOCIATION CONDITIONS

A statistical study of the fragmentation behaviour of 138 model peptid es, containing 3-9 amino acid residues (n = 3-9) under high-energy col lision conditions is presented. The aim was to identify characteristic patterns of ions in the spectra of peptides which can be translated i nto general rules to be used in the spectral interpretation and provid e a better insight into their fragmentation behaviour. It was found th at both number and nature of the amino acids are important factors dir ecting the fragmentation behaviour. The spectra of tri- and tetrapepti des exhibit a comparable probability for the formation of B-2- and Y ' '(n-2) ions, whereas larger peptides show a preference for the formati on of B-n-1 ions. This generally observed fragmentation pattern of pep tides is changed significantly when basic amino acid residues (Arg, Ly s and His) and/or Pro are present. Arginine appears to have the most p ronounced influence on the fragmentation behaviour and overrules that of the other amino acid residues.