Figure 4.

Bell-shaped dose-response for the basic model. (a) Bell-shaped dose response for the basic model when S_t is varied. Parameters used are: λ₋₁ = λ₁ = λ₂ = λ₋₂ = 0.1s⁻¹,k₁ = 1 s⁻¹,k₂ = 0.1s⁻¹,K_t = 2000μM,E_p = 0.1001E_k(−),E_p = 0.2E_k(−−),E_p = 0.08E_k(−.) (b) 2D parameter plot when αand P_t/K_t are varied. Parameters used are λ₋₁ = λ₁ = λ₂ = λ₋₂ = 0.1 s⁻¹,α = 0.1,K_t = 2000μM.$\left(R_{\max }^{S_t}\right)$ denotes the maximum of Rwith respect to S_t and $\left(R_0=\underset{S_t\to 0_{+}}{\text{lim}}R\right)$. Within a narrow region above the line P_t/K_t = α the ratio $R_{max}^{S_t}/R_0>1.05$, i.e., there is at least a 5% increase in $R_{max}^{S_t}/R_0$ compared to R₀.