Figure 3

Filtering of low frequency signals. A three tiered biochemical cascade with competing processes occurring at different time scales that is sufficient to filter signals at long time scales (Low pass filtering). a.) An initial stimulus activates a downstream species that confers a signal output and activates a downstream species that, through feedback, interacts with the species that carries the signal output. Superscripts (I) and (A) denote inactive and active forms of each chemical species and are omitted from the equations in the text. b.) parameter values were taken to be: υ = -1, $k_1^{+}=k_1^{-}=k_2^{+}=1.0$; $k_2^{-}$ = 0.1. k _f = 2.5 (solid lines), k _f = 1.0 (dashed lines), k _f = 0.5 (dotted lines), k _f = 0.1 (dash-dotted lines). c.) parameter values were taken to be: υ = -1, $k_1^{+}=k_1^{-}=k_2^{+}=k_f=1.0$. $k_2^{-}$ = 0.0 (solid lines), $k_2^{-}$ = 0.5 (dashed lines), $k_2^{-}$ = 1.0 (dotted lines), $k_2^{-}$ = 2.0 (dash-dotted lines).