FIGURE 2.

MS/MS analysis of panitide L3. A, S-alkylated panitide L3 was digested with endoproteinase Glu-C, generating two fragments with m/z values of 694.2 and 2486.1. B, MS/MS spectra of 694.2 Da fragment. C, MS/MS spectra of 2486.1 Da fragment. The peptides were digested with three different enzymes, endoproteinase GluC, trypsin, and chymotrypsin, as indicated under “Experimental Procedures.” The endoproteinase GluC fragments are shown here. The remaining sequence was obtained from other proteolytic fragments.