Fig. 6.
H2O2 input dynamic range for redox switches. Plots of Eq. 4A show the range of H2O2 concentrations to which thiol proteins with different reactivity respond. The following ktarget+H2O2 values were used: peroxiredoxin 2 (Prx2) – 1×107 M−1s−1; peroxiredoxin 5 (Prx5) – 3×105 M−1s−1; Kelch-like ECH-associated protein 1 (Keap1) – 140 M−1s−1; cell division cycle 25B (cdc25B) – 140 M−1s−1; protein tyrosine phosphatase 1B (PTP1B) – 24 M−1s−1; PTP1B in presence of bicarbonate (PTP1B + CO2) – 396 M−1s−1; and, src-homology 2 containing tyrosine phosphatase (SHP-2) – 20 M−1s−1. In (A) kswitchoff value was 2×10−3 s−1, while in (B) the influence of a range of kswitchoff values is shown for peroxiredoxin 5. Input H2O2 concentrations sustaining information transmission by redox switches are shown in green and were defined as the input eliciting a 10–90% oxidation of the protein. Below 10% oxidation, redox switch response is considered too weak to transmit efficiently the H2O2 signal, while above 90% oxidation, the response is near saturated to further increase in the H2O2 concentration.