Top-Down Metabolomics Approaches: Nitrogen- and Sulfur-Omics by Ultrahigh-Resolution Fourier Transform Ion Cyclotron Resonance-Mass Spectrometry

Abstract

Almost all metabolites that have potent pharmaceutical activity contain heteroatoms such as nitrogen (N) and sulfur (S). The huge chemical diversity of N- and S-containing metabolites (N- and S-metabolites) in organisms, including plants, delays the development of metabolomic studies for chemical assignment. The efficient understanding of the ions derived from the N- and S-metabolites in mass spectrometry-based metabolome data quickly opens the door of further research. Here we highlight metabolome approaches for N- and S-metabolites by ultrahigh-resolution Fourier transform ion cyclotron resonance-mass spectrometry. The use of monoisotopic ions and their counterpart isotopic ions including 15N or 34S in ultrahigh-resolution data enables the chemical assignment of known and unknown N- and S-metabolites in plants. We show some examples of the profiling of such metabolites. Finally, we discuss the future perspectives for the structure elucidation of unknown metabolites.