ABSTRACT
The measurement or estimation of metabolic fluxes is useful for the evaluation of metabolic networks and their control. In isotope tracer methods, the cells to be studied are provided with a substrate specifically labeled with a detectable isotope. Flux estimation based only on material balances is identical, in principle, to flux estimation using isotopic tracers and has been applied to many biochemical processes, including lysine synthesis and rat heart metabolism. The magnitude of the control coefficient is a measure of how important a particular enzyme is in the determination of the steady-state flux. The challenge in analyzing a metabolic network is determination of the flux control coefficients. It is possible to determine them directly by “enzyme titration” combined with the measurement of the new steady-state flux. Metabolic control analysis, especially with the innovations for determining flux control coefficients, is a powerful tool for the analysis of metabolic networks.
