Metabolomics

Metabolomics is the study of expressed metabolites (small molecules) in a cell, a tissue, an organ or an organism at definite time and conditions.

Metabolomic analysis is a dynamic study: metabolites composition, in terms of identity and quantity, depends on several factors such as the available nutriments, the environmental stimuli or the physiological conditions. Metabolites are of interest on their own or because of information they give on a particular biological activity.

The metabolome comparison of two subjects permits to link genotypes to phenotypes, the metabolome comparison of one subject in different conditions permits to understand the environment influence on the expressed phenotype.

Metabolomics allows a better understanding of systems biology than traditional biochemistry.

Our approach

Mass spectrometry coupled to liquid chromatography allows identifying and quantifying metabolites. Several methods are useful:

• Targeted analysis, detection and quantification of known metabolites,

• Metabolic profiling, identification of all metabolites in a same pathway or in a same chemical family,

• Metabolic fingerprint, metabolomes comparison,

• Metabolomic approach or metabonomics, non targeted identification and quantification of all metabolites in a biological sample.

These methods are done by high resolution nano LC-MS/MS coupled with bioinformatics tools and analysis methods such as DIA. It can be applied to different samples like biological fluids, tissues or cell culture from animal or vegetal origin, microorganisms or a gel electrophoresis band.

We are available to answer to your questions on this approach to see how it can be helpful for your projects.

Services and technologies

Targeted analysis

Absolute quantification by targeted method (PRM)

The PRM type targeted methods are considered as the most selective and sensitive mass spectrometry methods since, using the PRM scan mode, only components of interest are analyzed, and thus improves the sensitivity and signal to noise ratio. The use of a high resolution instrument (Orbitrap) coupled a quadrupole performing accurate ionic filtration of parent ions allows obtaining screening and quantification methods for which the sensitivity/specificity compromise is better than on a triple quadrupole instrument in classical PRM mode. The advantage of this targeted method type is to be able to follow the interesting metabolite in a robust and fast way. Furthermore, this method is easily transposable on triple quadrupole instrument type.

Metabolic profiling

An LC-MS/MS instrument analyses continuously the fractions obtained from HPLC separation of extract components. The mass spectrometer does every second an MS spectrum followed by 30 MS/MS fractionation on the most intense components. This information generated is compared to mass maps and spectra available in databases and it allows identifying the metabolites from the samples.

The method effectiveness and reliability is based on the accurate measurement of each metabolite mass, the high resolution mass spectrometer meets these needs.

Metabolic fingerprint

“Label-free” relative quantification

This method permits the qualitative and quantitative comparison of different subjects metabolomes. Typically this technique may be used to compare two conditions, for instance healthy vs unhealthy, and so to identify biomarkers which presence or quantity shows a physiological condition.

The samples LC-MS profiles are compared and the different metabolites pikes areas are measured. These areas are compared to those acquired for the same metabolites in a reference sample and so determining its relative quantity.

In same test, it is possible to identify metabolites by comparison with databases.

Quantification DIA

This method allows generating a large number of MS/MS spectra for a same sample and within a very large mass range. A high resolution mass spectrometer with high speed data acquisition is necessary.

Due to the increase of the assay reproducibility and specificity, this technique, compared to classical “label-free” quantification, allows absolute metabolite quantification in a sample.

The metabolomic approach or metabonomics

Structural determination by unknowns screening

The unknowns screening is a method which requires a mass spectrometer with high mass accuracy and high resolution. The component gross chemical formula is deducted from its accurate mass and its isotopic distribution determined by LC-MS. Its structure is deducted from its MS/MS fragmentation spectra. This information allows identifying and quantifying low molecular weight chemical components such as metabolites, for which no information exist in databases.

Custom Services

Our teams are fully available to define best strategies for your project and answer to your questions.

• Conception : ID-Alizés