Metabolomics 8/1/03. By RT The global study of all the small molecules produced in the human body.

The proteome is the full complement of proteins produced by the human genome at any one time. Unlike the genome, which is the same in most cells, the proteome is very dynamic. Distinct sets of proteins are produced in different cell types and developmental stages.

The proteome is also influenced by the environment and events going on inside the cell, such as cell division. Changes in the proteome reflect different patterns of gene expression and protein modification (see Proteomics ).

Proteomic analysis methods such as two-dimensional polyacrylamide gel electrophoresis and mass spectrometry allow the abundance and distribution of many proteins to be determined simultaneously. However, the functional consequences of changes to the proteome are reported only indirectly. If the abundance of a particular enzyme changes, one can guess that the substrate of that enzyme will be reduced and the product will accumulate. However, a more direct approach is to measure the levels of these small molecules, or metabolites. The global analysis of metabolites is known as metabolomics.

The advantage of metabolomic analysis is that the biochemical consequences of mutations, changes in the environment and treatment with drugs can be observed directly. This may help in the development of new drugs. It may also help us to understand how drugs work, interact and cause side effects.

Metabolomics is a relatively new discipline and techniques for high-throughput metabolic profiling are still under development. No single technique is suitable for the analysis of all different types of molecule, so a mixture of techniques is used. Methods such as gas chromatography, high-pressure liquid chromatography and capillary electrophoresis are used to separate metabolites according to various chemical and physical properties. The molecules are then identified using methods such as mass spectrometry.