Table 5.
Parameters related to NO- and ROS-mediated effects on Ca2+ signaling
Parameter | Definition | Value | Reference |
---|---|---|---|
KM, cGMPMLCP | cGMP concentration at half-maximal activation of MLCP (Eq. 25) | 5.5 μM | 53 |
KM, cGMPSERCA | cGMP concentration at half-maximal activation of SERCA (Eq. 29) | 500 nM | Est. |
KM, cGMPPMCA | cGMP concentration at half-maximal activation of PMCA (Eq. 31) | 1 μM | Est. |
KM, cGMPKCa | cGMP concentration at half-maximal activation of KCa channels (Eq. 27) | 0.55 μM | (53) |
VM, cGMPKCa | Constant for activation of KCa channels by cGMP (Eq. 27) | 66.9 mV | (53) |
KM, NOKCa | NO concentration at half-maximal activation of KCa channels (Eq. 27) | 200 nM | (53) |
VM, NOKCa | Constant for activation of KCa channels by NO (Eq. 27) | 100 mV | (53) |
VCa | Constant for voltage-dependence of KCa channel open probability (Eqs. 26 and 27) | −53.7 mV | (53) |
VB | Constant for voltage-dependence of KCa channel open probability (Eqs. 26 and 27) | 283.7 mV | (53) |
kKCa | Constant for voltage-dependence of KCa channel open probability (Eq. 26) | 30.8 mV | (53) |
KM, O2−SERCA | O2− concentration at half-maximal inhibition of SERCA (Eq. 33) | 20 μM | Est. |
KM, H2O2SERCA | H2O2 concentration at half-maximal inhibition of SERCA (Eq. 34) | 66 μM | (24) |
KM, O2−NAK | O2− concentration at half-maximal inhibition of Na+-K+-ATPase (Eq. 36) | 1.6 μM | Est. |
KM, H2O2NAK | H2O2 concentration at half-maximal inhibition of Na+-K+-ATPase (Eq. 36) | 0.56 mM | (16) |
KM, H2O2MLCP | H2O2 concentration at half-maximal inhibition of MLCP (Eq. 37) | 1 μM | Est. |
αMLCP | Constant for H2O2-mediated inhibition of MLCP (Eq. 37) | 4.0 | See text |
SERCA, SR Ca2+-ATPase; MLCP, myosin light chain phosphatase; PMCA, plasma membrane Ca2+-ATPase.