Sequence Informative Fragmentation in 252 Cf Plasma Desorption Mass Spectrometry

In the field of peptide chemistry plasma-desorption mass spectrometry (PDMS) is now fully accepted as a useful method for obtaining accurate molecular weight information on peptides up to about 25 kDa molecular weight. Furthermore it has given useful information in C-terminal sequence determination by analyzing the trunk peptide instead of the liberated amino acids [1]. In addition, the method is very useful in peptide mapping by the method introduced by Morris et al. [2] applying fast atom bombardment (FAB) mass spectrometry. In these experiments PDMS has mainly been used as a technique to obtain molecular weight information. Nevertheless in some reports the presence of sequence information has been shown in smaller peptides [3–6]. During peptide mapping of recombinant IL-3 however we obtained a spectrum of a 4600 Da peptide containing considerable sequence informative fragmentation.