Fig 6. Activation of the compensatory flux for reaction scheme of Fig 5 and corresponding Eqs 6, 2 and 7 with n = 4.
Left panel: Concentrations of A and E as a function of time with different k5/k6 rate constants. Blue curves A3 and E3 correspond to the calculations without C (Fig 4 with n = 4). Right panel: Concentrations of C with different k5/k6 rate constants as a function of time. Phase 1: the controller is at steady state at its set-point Aset = 5.0 at constant k1 = 2.0. Phase 2: k1 increases exponentially according to the inset in the left panel of Fig 3. k5 and k6 values and initial concentrations for the different Ai, Ei, Ci curves: i = 1, k5 = 10.0, k6 = 0.01, A0 = 5.0, E0 = 2.412, C0 = 39.81; i = 2, k5 = 1.0, k6 = 0.1, A0 = 5.0, E0 = 0.9, C0 = 1.0; i = 3, no C (Fig 4 with n = 4); i = 4, k5 = k6 = 0.1, A0 = 5.0, E0 = 0.531, C0 = 0.158. Other rate constant values: k2 = 1 × 105, k3 = 5 × 103, k4 = 1 × 103, KM = 1 × 10−6, KI = 0.1.