SE157:/DS2

Sample Set Information

ID	TSE1313
Title	Top-down Metabolomic Approaches for Nitrogen-Containing Metabolites.
Description	Streamlining the processes that reveal heteroatom-containing metabolites and their biosynthetic genes is essential in integrated metabolomics studies. These metabolites are especially targeted for their potential pharmaceutical activities. By using a Fourier-transform ion cyclotron resonance-mass spectrometry (FTICR-MS) instrument, we provide top-down targeted metabolomic analyses using ultrahigh-resolution liquid chromatography-mass spectrometry (LC-MS), high-resolution matrix-assisted laser desorption/ionization (MALDI), and high-resolution imaging mass spectrometry (IMS) with 15N labeling of nitrogen-containing metabolites. In this study, we efficiently extract known and unknown chemicals and spatial information from the medicinal plant Catharanthus roseus, which sources several cancer drugs. The ultrahigh-resolution LC-MS analysis showed that the molecular formula of 65 N-metabolites were identified using the petals, peduncles, leaves, petioles, stems, and roots of the non- and 15N-labeled Catharanthus plants. The high resolution MALDI analysis showed the molecular formula of 64 N-metabolites using the petals, leaves, and stems of the non- and 15N-labeled Catharanthus. The chemical assignments using molecular formulas stored in databases identified known and unknown metabolites. The comparative analyses using the assigned metabolites revealed that most of the organ-specific ions are derived from unknown N-metabolites. The high-resolution IMS analysis characterized the spatial accumulation patterns of 32 N-metabolites using the buds, leaves, stems, and roots in Catharanthus. The comparative analysis using the non- and 15N-labeled IMS data showed the same spatial accumulation patterns of a non- and 15N-labeled metabolite in the organs, showing that top-down analysis can be performed even in IMS analysis.
Authors	Nakabayashi R, Hashimoto K, Toyooka K, Saito K.
Reference	Anal Chem. 2017 Mar 7;89(5):2698-2703. doi: 10.1021/acs.analchem.6b04163. Epub 2017 Feb 22.
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PubMed

Data Analysis Details Information

ID	DS2
Title	Data Analysis (LC-MS)
Description	All data were calibrated with m/z 235.1804 (lidcaine, [M + H]+). After noise reduction (<100000 counts), the N-ion candidates were extracted using the theoretical mass and signal intensity differences between the N-ions and their 15N-substituted counterparts (0.9970 ± 0.001 Da and 0.36 ± 1.00%, respectively). Elemental composition candidates were estimated in DataAnalysis under the following conditions: adduct type, [M + H]+; tolerance, 4 mDa; number of nitrogen atoms in formula, ≥1; charge, +1; Check rings plus double bonds, ≤80; filter H/C ration, ≤3. Finally, the molecular formulas of the 65 N-ions were determined from the mass shifts of the N-ions from the non-labeled data to the 15N-labeled data.
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