The results obtained for three other type 2 peptides with the hydrolyzed thiosuccinimide linker ((P2-P4)H, (P1-P3)H, and (P3-P4)H) and analyzed by MALDI-MS/MS with and without collision gas (Fig. ) confirmed the results obtained for (P1-P2)H (Figures and). In all of them Pn+71 were the most intense signal in the MALDI-MS/MS spectra. The relative intensity of Pn+71 and Pn+98 in all MALDI-MS/MS spectra seems to be modulated by the relative basicity of the C-terminal amino acids present in the two crosslinked peptides.