Skip to main content
Figure 7 | BMC Bioinformatics

Figure 7

From: An analytic and systematic framework for estimating metabolic flux ratios from 13C tracer experiments

Figure 7

An example of using fragment independence to obtain new isotopomer constraints for a reactant. The mass isotopomer distributions of striped metabolites are assumed to be measured. Fragments M1|E and M2 belong to the same fragment equivalence class. Thus, D m (M1|E) can be derived from D m (M2) by the measurement propagation inside equivalence classes. Furthermore, fragments M5|E' and M5|F' dominate fragments M1|E and M1|F, and the bond between M1|E and M1|F is broken in all pathways producing M1 from M5. Thus, M1|E and M1|F are statistically independent, and D m (M1|F) can be deduced from D m (M1) and D m (M1|E) by utilizing Equation 7. Computed D m (M1|F) can then be propagated to M4, as M1 and M4 belong to the same fragment equivalence class. Finally, D m (M4) helps to solve the ratios of fluxes entering to M3.

Back to article page