Toward metabolome-based 13C flux analysis: A universal tool for measuring in vivo metabolic activity

Abstract

Intracellular metabolic rates cannot be directly assessed from metabolome concentrations and vice versa. For most biological questions, stable isotope tracers must be administered and tracked to effectively determine metabolic fluxes by means of numerous computational steps. Although flux analysis targets the same analytes as metabolomics, priority is given to measuring their exact isotopic distribution rather than their concentration. In the first part of this chapter, I describe principles and issues of current 13C flux analysis methods, following the entire process from experimental design, to detection of isotopic distributions, and data interpretation. Notably, current practice largely relies on the labeling patterns of protein-bound amino acids, because of their abundance and stability. In the second part, I focus on achievements, challenges, and opportunities of metabolome-based 13C flux analyses, which are emerging in response to the need to tackle larger networks, higher cells, and to improve both spatial and temporal resolution. © 2007 Springer-Verlag Berlin Heidelberg.