TABLE 7.
Parameters for Ca buffers
| Buffer | Compartment | Bmax (μmol/l cytosol*) | Kd (μM) | koff (s−1) | kon (μM−1s−1) |
|---|---|---|---|---|---|
| Troponin C | Cytosol | 70 | 0.6 | 19.6 | 32.7 |
| Troponin C Ca-Mg (Ca) | Cytosol | 140 | 0.0135 | 0.032 | 2.37 |
| Troponin C Ca-Mg (Mg) | Cytosol | 140 | 1111 | 3.33 | 0.003 |
| Calmodulin | Cytosol | 24 | 7 | 238 | 34 |
| Myosin (Ca) | Cytosol | 140 | 0.0333 | 0.46 | 13.8 |
| Myosin (Mg) | Cytosol | 140 | 3.64 | 0.057 | 0.0157 |
| SR | Cytosol | 19 | 0.6 | 60 | 100 |
| SL | SL | 37.4 | 13 | 1300 | 100 |
| SL | Junction | 4.6 | 13 | 1300 | 100 |
| SLHigh | SL | 13.4 | 0.3 | 30 | 100 |
| SLHigh | Junction | 1.65 | 0.3 | 30 | 100 |
| Indo-1 | Cytosol | 25 | 0.6 | 60 | 100 |
| Indo-1 | SL | 0.77 | 0.6 | 60 | 100 |
| Indo-1 | Junction | 0.02 | 0.6 | 60 | 100 |
| Fluo-3 | Cytosol | 25 | 1.1 | 110 | 100 |
| Fluo-3 | SL | 0.77 | 1.1 | 110 | 100 |
| Fluo-3 | Junction | 0.02 | 1.1 | 110 | 100 |
| Calsequestrin | SR | 140 | 650 | 65,000 | 100 |
*
Concentrations in the actual compartments can be calculated assuming 11% of membrane-bound components are in the junctional cleft and 89% are in the SL compartment.