title: Isotopically non-stationary metabolic flux analysis: complex yet highly informative.
abstract: Metabolic flux analysis (MFA) using isotopic tracers aims at the experimental determination of in vivo reaction rates (fluxes). In recent years, the well-established 13C-MFA method based on metabolic and isotopic steady state was extended to INST-MFA (isotopically non-stationary MFA), which is performed in a transient labeling state. INST-MFA offers short-time experiments with a maximal information gain, and can moreover be applied to a wider range of growth conditions or organisms. Some of these conditions are not accessible by conventional methods. This comes at the price of significant methodological complexity involving high-frequency sampling and quenching, precise analysis of many samples and an extraordinary computational effort. This review gives a brief overview of basic principles, experimental workflows, and recent progress in this field. Special emphasis is laid on the trade-off between total effort and information gain, particularly on the suitability of INST-MFA for certain types of biological questions. In order to integrate INST-MFA as a viable method into the toolbox of MFA, some major challenges must be addressed in the coming years. These are discussed in the outlook.
authors.affiliation: Forschungszentrum Jülich, IBG-1: Biotechnology, 52425 Jülich, Germany. Electronic address: w.wiechert@fz-juelich.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wiechert
authors.forename: Katharina
authors.initials: K
authors.lastname: Nöh
mesh_terms: D000818:Animals; D002247:Carbon Isotopes / Q000032:analysis; D007553:Isotope Labeling / Q000379:methods*; D064688:Metabolic Flux Analysis
chemical_list: D002247:Carbon Isotopes