title: Defining the metabolome: size, flux, and regulation.
abstract: Renewed interest in metabolic research over the last two decades has inspired an explosion of technological developments for studying metabolism. At the forefront of methodological innovation is an approach referred to as "untargeted" or "discovery" metabolomics. The experimental objective of this technique is to comprehensively measure the entire metabolome, which constitutes a largely undefined set of molecules. Given its potential comprehensive coverage, untargeted metabolomics is often the first choice of experiments for investigators pursuing a metabolic research question. It is important to recognize, however, that untargeted metabolomics may not always be the optimal experimental approach. Conventionally, untargeted metabolomics only provides information about relative differences in metabolite pool sizes. Therefore, depending on the specific scientific question at hand, a complementary approach involving stable isotopes (such as metabolic flux analysis) may be better suited to provide biological insights. Unlike untargeted metabolomics, stable-isotope methods can provide information about differences in reaction rates.
authors.affiliation: Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland. Electronic address: zamboni@imsb.biol.ethz.ch.
authors.forename: Nicola
authors.initials: N
authors.lastname: Zamboni
authors.affiliation: Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA 92037, USA. Electronic address: asaghatelian@salk.edu.
authors.forename: Alan
authors.initials: A
authors.lastname: Saghatelian
authors.affiliation: Department of Chemistry and Department of Medicine, Washington University, St. Louis, MO 63130, USA. Electronic address: gjpattij@wustl.edu.
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Patti
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007553:Isotope Labeling / Q000379:methods*; D013058:Mass Spectrometry; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D015203:Reproducibility of Results; D015398:Signal Transduction