Table 3. Summary of the parameters of Hill fits to the [Ca2+] and [Mg2+] dependences of P0 in the absence and presence of DHPR C-region peptides.
DHPR C-region peptide | Experimental conditions | X2+ | Pmax | Ki (μM) | ni | N | n |
---|---|---|---|---|---|---|---|
– | 250 mM Cs+, 2 mM ATP | Ca2+ | 0.86±0.03 | 980±055 | 3.0±0.6 | 5 | 51 |
50 μM CS | 250 mM Cs+, 2 mM ATP | Ca2+ | 0.84±0.06 | 2300±400 | 2.6±1.1 | 4 | 31 |
– | 100 mM Cs+, 2 mM ATP | Ca2+ | 0.73±0.06 | 210±037 | 2.0±0.5 | 3 | 40 |
50 μM CS | 100 mM Cs+, 2 mM ATP | Ca2+ | 0.49±0.05 | 460±071 | 4.5±2.8 | 3 | 40 |
– | 100 mM Cs+, 2 mM ATP | Mg2+ | 0.69±0.07 | 250±40 | 2.3±0.7 | 5 | 70 |
50 μM CS | 100 mM Cs+, 2 mM ATP | Mg2+ | 0.46±0.07 | 420±110 | 2.7±2.0 | 6 | 65 |
25 μM CS1 | 100 mM Cs+, 2 mM ATP | Mg2+ | 0.58±0.06 | 570±120 | 1.7±1.4 | 4 | 75 |
25 μM CS2 | 100 mM Cs+, 2 mM ATP | Mg2+ | 0.62±0.07 | 350±41 | 3.2±2.0 | 4 | 12 |
*Native | 250 mM Cs+ | Ca2+ | 710±80 | 18 | |||
*MHS | 250 mM Cs+ | Ca2+ | 1160±220 | 13 | |||
*Native | 100 mM Cs+ | Ca2+ | 204±32 | 18 | |||
*MHS | 100 mM Cs+ | Ca2+ | 957±250 | 9 |
* Native and MHS refer to normal and malignant hyperthermia-susceptible RyRs respectively from pig skeletal muscles [39].