Dynamics and models of an adaptive enzyme network. (A) A schematic illustration of adaptation dynamics: sensitivity refers to the magnitude of the change in the output after the introduction of an external signal, and precision refers to the ability of the system returning to its pre-stimulus state after being perturbed by the external signal. Two quantities, a sensitivity score and a precision score, can be defined to measure these two dynamic properties (see Methods for details). (B) Network topology of the chemotaxis machinery in E. coli. (C) An enzyme network with a negative feed-back loop, known as the NFBLB model, that exhibits similar topology to the E. coli chemotaxis circuit where v
) (n = A, B or C) represents the activation (deactivation) process of the rate equation for node n.