Before revision:  We illustrate our approach with the directed network of the central carbon metabolism of Escherichia coli , and study its properties in four relevant biological scenarios. Our results show that both flow and network structure depend drastically on the environment: networks produced from the same metabolic model in different contexts have different edges, components, and flow communities, capturing the biological re-routing of metabolic flows inside the cell .
After revision:  We illustrate our approach with the directed network of the central carbon metabolism of Escherichia coli and study the derived graphs under various growth conditions. The results reveal drastic changes in the topological and community structure of the metabolic graphs, which capture the re-routing of metabolic flows inside the cell .