Nanoelectrospray spectrum of in-gel tryptic digest of gp114. Peaks labeled with Tr originated from the autolysis of trypsin; peaks labeled with IgG were identified as tryptic peptides from IgG antibodies by Mascot searches. Tandem mass spectra of other peaks were not matched by Mascot and were subjected to de novo interpretation (Figure 3). Inset: MALDI TOF peptide mass map of the tryptic digest of the gp114 band obtained from the gel shown in figure 1c, lane A. Deglycosylated gp114 gave the same spectrum (not shown). Peaks of autolysis products of trypsin labeled with Tr. Peaks of peptides originating from gp114 are designated with their m/z.