Figure 4. Experimental flux control coefficients.
(A) Schematic of experimental flux control analysis. Cells are pre-incubated with 13C glucose and treated with differing concentrations of inhibitors that target glycolysis at different points in the pathway. Media and intracellular metabolites are collected, subjected to (liquid chromatography high resolution mass spectrometry) LC-HRMS, and subjected to flux analysis. (B) Changes in metabolite levels observed from treatment with 3PO an inhibitor of PFK2. (C) Changes in metabolite levels observed from treatment with IA an inhibitor of GAPDH. (D) Changes in metabolite levels observed from treatment with FX11 and inhibitor of LDH. For B–D, the logarithm (log2) of the fold change of treated to vehicle across intermediates in glycolysis is shown for each concentration of compound denoted in the figure legend. Abbreviations are the same as described in Figure 1 except that HP denotes all hexose phosphates that were measured and not distinguished in the current mass spectrometry method. (E) Lactate flux from glucose as a function PFK2 inhibition. (F) Lactate flux from glucose as a function GAPDH inhibition. (G) Lactate flux from glucose as a function LDH inhibition. For E–G, the plot on the left shows the measured glucose to lactate flux as a function of the estimated fraction of enzyme inhibited (left) inhibitor concentration (right).