Searching for Metabolic Biomarkers

Biomarker Searching by LCMS-IT-TOF

■ Searching for Metabolic Biomarkers Using the Combination of High-Accuracy Mass Spectrometry (MSn) with Multivariate Analysis and Formula Prediction Tool

Low-molecular compounds in biological samples, such as metabolic components including endogenous metabolites and drugs in blood and tissue, are important biomarker candidates.
The LCMS-IT-TOF High-Performance Liquid Chromatograph-Mass Spectrometer offers highly accurate mass information for many metabolites. This system combines separation by an optimized LC system with a high-performance hybrid (quadrupole ion trap (QIT)/ time-of-flight (TOF)) mass spectrometer.

The LCMS-IT-TOF analysis of biomarkers in blood plasma of a rat model for type II diabetes (Zucker rat) is introduced below.
The pretreated sample was analyzed by LCMS-IT-TOF, and primary component analysis using multivariate analysis software used to determine the differences between the normal and type II diabetes model rat groups.
The quantitative differences between the two groups in these results were then analyzed, focusing on the lipid components. Multiple ion chromatograms were plotted for them/zvalues. The accurate mass information and MSn were applied for formula prediction using Formula Predictor software and compound identification through database searching.

The Formula Predictor software yielded a single formula candidate, which the database search identified as 1-Palmitoyllysophatidylcholine. The other lipids were identified in the same manner.

Therefore, LCMS-IT-TOF can obtain MSn information with high mass accuracy. Using Shimadzu's unique Formula Predictor software on this MSn information permits accurate identification of the composition formula.

LCMS-IT-TOF Liquid Chromatograph Mass Spectrometer

LCMS-IT-TOF is a liquid chromatograph mass spectrometer that combines a high-performance liquid chromatograph with an ion-trap (IT) mass spectrometer and time-of-flight (TOF) mass spectrometer. It combines the MSn performance of the ion-trap mass spectrometer with the high-resolution, high-accuracy mass measurements of the time-of-flight mass spectrometer to achieve highly accurate mass measurements that were unheard of with conventional LC/MS/MS.
It is a powerful tool for searching low-molecular-weight biomarkers.

Metabolomics Analysis Software

ProfilerTM AM+ metabolomics analysis software performs statistical analysis of the huge amount of data obtained by a mass spectrometer. It compares and statistically overlays two or more sample sets to identify the metabolites that have the greatest effect on differences between the sample sets.
ProfilerTM AM+ permits principle component analysis (PCA) and clustering analysis by comparing sets and is ideal for searching for components (biomarker candidates) exhibiting characteristic changes from large volumes of data.
See MetIDSolution Metabolite Structural Analysis Software for the high-throughput and comprehensive detection and identification of metabolites.

Formula Predictor Software

The software offers more than formula predictions from exact masses. It can narrow down the number of metabolite candidates by taking into account the candidate isotope patterns and the MSn information.
It offers highly reliable identification of metabolite compositions.