Figure 5.

NPLP1 sequence with peptides identified in this study and/or previously. In blue are three peptides (MTYamide, IPNamide and VQQ), which were identified both previously and in this study with MALDI-TOF/TOF MS/MS. In purple are the regions containing three novel molecules we detected and identified. One peptide we identified corresponded to the predicted NPLP1-2, which we detected with an intact C-terminal lysine (DPK peptide), marked “K” in red. Also identified were two distinct peptides corresponding to the predicted NPLP1-3, with (GAE) and without (QRAamide) a C-terminal GAE sequence marked in red. The NPLP1-3 variant without the GAE fragment was observed to be amidated (QRAamide). We also detected and tentatively assigned, but not identified by fragmentation, an ion mass corresponding to the peptide outlined in orange, which has been reported with (as APK peptide) and without (as NAP peptide) a C-terminal K (marked in red). Our tentative assignment corresponded to the peptide with C-terminal K intact. Dibasic residue cleavage sites are shown underlined and bolded. Additional peptides that have been predicted but not identified are not explicitly highlighted.