Figure 2.

Log-log plot of signal molecule production, κ_s, as a function of activated regulator concentration, r_a = [R₂S₂]. The feedback loop ignites when the signal molecule production starts rising from the background level. Note that this point can be several orders of magnitude lower than the dissociation constant for the binding of R₂S₂ to the promoter. In this figure, an induction factor of k_s/b_s = 100 was assumed.