Abstract
We propose a concept of "metabolite annotation", and report an application of metabolite annotation procedure to analyze plant metabolome data obtained by LC/FT-ICR-MS. We tentatively define "metabolite annotation" as a series of processes including clustering of MS peaks derived from single metabolites, and providing metabolite peaks with chemical information such as molecular formulas, MS/MS fragmentation patterns, and UV/visible absorption patterns. We used data of tomato fruit samples obtained by LC/FT-ICR-MS to establish metabolite annotation procedure. Combination of accurate m/z values and relative intensity of isotopic ions allowed us to cluster peaks and narrow down the candidate molecular formulas. We currently provide annotation to more than 300 metabolite peaks. As a result of tomato analysis, we conclude that metabolite annotation is informative for structural elucidation, and that metabolite annotation allows coherent comparison of metabolite peaks in numbers of LC/FT-ICR-MS data. Additionally, a comprehensive metabolite annotation facilitates a prediction of metabolic pathway.
