Figure 2

Effect of increasing glucose on cell energetics. Extracellular glucose concentration was varied and the steady-state simulations of the model parameters represented. Simulations were run with the basic set of parameters (Tables 2 and 3). A: J_glu is the rate of the glucokinase reaction (for comparison with other fluxes the amount of 2 J_glu is represented since two pyruvate molecules are synthesized from one molecule of glucose), jpyr is the rate of pyruvate decarboxylation, jtnadh is the flux through the NADH shuttles measured as the rate of cytoplasmic NAD⁺ production from cytoplasmic NADH, J_LDH is the lactate flux catalyzed by lactate dehydrogenase; B: [NADH]_c and [NADH]_m are cytoplasmic and mitochondrial NADH, [Pyr] is the pyruvate concentration, [G3P] is the cytoplasmic glyceraldehydes 3-phosphate concentration; C: Jhres is the rate of proton pumping through ETC, J_ph is the proton flux through the F₁F₀ ATPase, Jhi is the leak of protons from mitochondria; D: Ψ_m is the mitochondrial membrane potential, [ATP]_c/[ADP]_c is the cytoplasmic ATP/ADP ratio; E: [Ca²⁺]_c and [Ca²⁺]_m are the concentration of free Ca²⁺ in cytoplasm and mitochondria.