Figure 1.

Switching time. We set the cell volume to V = 8 × 10⁻¹⁶ l. The following set of parameters have been used: K = 0.5 µM and μ = 1 min⁻¹. The two steady states are L = 0.2 µM and H = 0.8 µM. We consider both a switch (a) from low state to high state (L → H) and (b) from high state to low state (H → L). We chose θ = 0.9. Stochastic fluctuations do not influence significantly the time required to reach a fraction θ of the steady state concentration (solid line, deterministic; dashed line, stochastic).