Table 1. Model diffusion and buffering constants.
| Species | Concentration (μM) | Diffusion coefficient (10−10 m2/s) | k on (μMs-1) | k off (s-1) |
|---|---|---|---|---|
| Ca 2+ | 0.1 | 3.0 | ||
| ATP(Ca) | 0.2 a | 1.0 | 13.7 b | 3.0x104 |
| Mg 2+ | 1000 | 0 a | 100 | 31 |
| ATP(Mg) | 495 a | 1.0 | 3.3x10-4 | 3 |
| Fluo-3 | 100 | 0.7 | 48.8 | 43.9 |
| Troponin C | 100 | 0 | 200 | 200 |
Table gives constants for the model which are based on previous cardiac simulation studies[29, 30] with minor adjustments in buffering parameters improve the fit to experimental data.
a The total ATP concentration was 5 mM, which was distributed among free, Ca2+ bound and Mg2+ bound forms according to equilibrium conditions.
b Diffusion of Mg2+ was ignored as tests showed that negligible gradients in Mg2+ developed.