Metabolic flux analysis

Metabolic Flux Analysis and Metabolic Control Analysis... 

Iwatani, S., Yamada, Y. andUsuda, Y. (2008) Metabolic flux analysis in biotechnology processes. Biotechnology Letters, 30, 791-799. 

Bushell, M.E., Kirk, S., Zhao, H.-J. and Avignone-Rossa, C.A. (2006) Manipulation of the physiology of clavulanic acid biosynthesis with the aid of metabolic flux analysis. Enzyme and Microbial Technology, 39, 149-157. 

Figure 14. Principle for measuring bidirectional fluxes by 13C metabolic flux analysis. In a carbon labeling experiment, 1 13C glucose is provided in the medium, and the culture is grown until a steady state is reached. Glucose can either go directly via the hexose phosphate pool (Glu 6P and Fru 6P) into starch, resulting in labeling hexose units of starch only at the Cj position, or it can be cleaved to triose phosphates (DHAP and GAP), from which hexose phosphates can be resynthesized, which will result in 50% labeling at both the Ci and the C6 position (assuming equilibration of label by scrambling at the level of triose phosphates). From the label in the hexose units of starch, the steady state fluxes at the hexose phosphate branchpoint can be calculated for example, if we observe 75% label at the Ci and 25% at the C6 position, the ratio of vs to V7 must have been 1 to 1. All other fluxes can be derived if two of the fluxes of Vi, V6, and V7 are known (e.g., V2 vi V3 V5 + v6).

U. Sauer, N. Zamboni, and E. Fischer, FiatFlux a software for metabolic flux analysis from 13C glucose experiments. BMC Bioinform. 6, e209 (2005). 

I. G. L. Libourel and Y. Shachar Hill, Metabolic flux analysis in plants From intelligent design to rational engineering. Annu. Rev. Plant Biol. 59, 625 650 (2008). 

Metabolic Flux Analysis Using Mass Spectrometry... 

To illustrate and evaluate the different methods available, the following chapter gives a short overview on the most important methods for sample introduction, ion formation, and mass separation with respect to metabolic flux analysis. For a more detailed insight into modern MS methods the reader is addressed to recent overviews [e.g. 42-44]. 

The dominating method of ion formation in metabolic flux analysis is electron impact. It might be supplemented in the future by novel methods, such as matrix assisted laser desorption and electrospray. Additional techniques such as chemical ionization, fast atom bombardment or inductively coupled plasma ionization are only of minor importance and not further discussed in this context. 

The following chapter shows the application of MS to metabolic flux analysis with different examples. Whereas some of them focus on flux quantification of only a single or a few selected reactions, others aim at the analysis of larger parts of the metabohsm. The overview given should illustrate the broad application potential of MS for metabohc flux analysis by examples from different fields of research. The majority of studies belongs to the medical field, whereas so far only few examples can be found in the area of biochemical engineering. 

Wittmann C, Heinzle E (2000) Metabolic flux analysis of lysine producing Corynebac-... 

Matsuda, F., Morino, K., Ano, R., Kuzawa, M., Wakasa, K., Miyagawa, H. (2005). Metabolic flux analysis of the phenylpropanoid pathway in elicitor-treated potato tuber tissue. Plant Cell Physiol., 46,454 66. 

Polzin JJ, Rorrer GL, Cheney DP (2003) Metabolic Flux Analysis of Halogenated Monoterpene Biosynthesis in Microplantlets of the Macrophytic Red Alga Ochtodes secundiramea. Biomol Eng 20 205... 

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