Perturbation reaction subnetwork of gdh1/GDH2 mutant under anaerobic conditions. Subnetwork illustrates the highly perturbed anaerobic reactions of similar Zreaction magnitude to the reactions in Figure 3. A significantly larger number of reactions indicates mutant metabolic effects are more widespread in the anaerobic environment. The network shows that perturbed pathways converge on glutamate, the main site in which the gdh1/GDH2 modification was introduced, which suggests that the direct genetic perturbation effects are amplified under this environment. Metabolite abbreviations are found in Additional file 1.