Figure 1. PIS mass spectrometric analysis to screen for PHT biosynthetic intermediates.
(A) high resolution mass spectrum of PHTs (inset is fragmentation pattern of PHT); (B) tandem mass (MS2) spectrum of PHTs; (C) tandem mass (MS3) spectrum of daughter ions with m/z ratio at 452.3 in panel (B); (D) chromatogram of PIS mass spectrometric analysis; (E) high resolution mass spectrum of novel ions with m/z ratio at 417.2568 (inset is fragmentation pattern of Cit-Ala-hArg); (F), tandem mass spectrum of ions with m/z ratio at 417.2568.