Figure 6.

Simulation results for frequency modulation of the Novak–Tyson model with checkpoints inactive. Contour plot shows the effects of v_s and the inhibitor binding rate on the CDC frequency. Parameter values for the model are given in ref. 8. The dissociation constant for the inhibitor is K_d = 0.1. Oscillations at the natural frequency (f_n) are marked by the thick black contour line (f_n = 0.0118 min⁻¹). Above the f_n contour, the frequency of oscillations is reduced; below the contour, the frequency is increased.