Enzymatic cleavage directly on the probe tip for mass spectrometric identification of peptides

Fast atom bombardment mass spectrometry was used in direct combination with enzymatic cleavages by endopeptidases for the identification of peptides derived from recombinant proteins. By this fast and simple reaction on the probe tip, the enzymes produced a mixture of smaller peptides. Molecular weights were calculated in advance and used for verification of the amino acid sequence of the original peptide as well as for partial structure determinations. Since the enzymatic reaction took place directly on the probe tip, sample material and time was saved. This technique may be applied especially in such cases where mass spectrometry alone does not give sufficient information and if the mass range of the instrument is limited, e.g. to 2000 daltons.