Figure 4From: Bell-shaped and ultrasensitive dose-response in phosphorylation-dephosphorylation cycles: the role of kinase-phosphatase complex formationBell-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 = 2000μ M,E p = 0. 1001E k (−),E p = 0. 2E k (−−),E p = 0. 08E k (−.) (b) 2D parameter plot when α and P t /K t are varied. Parameters used are λ−1 = λ1 = λ2 = λ−2 = 0. 1 s−1,α = 0. 1,K t = 2000μ M. R max S t denotes the maximum of R with respect to S t and R 0 = lim S t → 0 + R . 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.Back to article page