FIG 3.
Mass spectrometric analysis of processed CSP. CSP samples were treated with purified SepM. After removal of the protein by centrifugation, the samples were desalted on a reverse-phase C4 column and then subjected to matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) ESI mass spectrometry analysis. Cleavage occurs between the residues shown in bold (top panel), which were mutated as indicated (middle and bottom panels). The theoretical peptide masses are shown next to the sequences in parentheses.