(A) Network diagram indicating key reactions and metabolites included in the INST-MFA model. (B) Fluxes estimated by INST-MFA. Abbreviations: ALS, acetolactate synthase; PK, pyruvate kinase; PDH, pyruvate dehydrogenase; CS, citrate synthase; MDH net, malate dehydrogenase (net flux from oxaloacetate to malate); ME, malic enzyme; PPC, PEP carboxylase. Data ± SEM, where SEM was calculated from the upper (UB) and lower bounds (LB) of the 95% flux confidence intervals (Table S1) using the formula SEM = (UB-LB)/3.92. n = 3. *p < 0.05.