Table 2.
Ca2+ sensitivity and cooperativity of activation. *P value ≤.05 compared to nfTm; **P value ≤.01 compared to nfTm; else, P value >.05 (no significant difference from nfTm). The Hill factor h and pCa50 (Ca sensitivity) were deduced by fitting the pCa-tension (or pCa-stiffness) data to (1). In all experiments, temperature was 25°C, ionic strength was 200 mM, and pH was adjusted to 7.00. The data were individually fitted to (1), averaged, and tabulated with ±SEM. †Data from [13].
| nfTm (control) | ∆2Tm | ∆3Tm | Acetyl Tm† | Units | |
|---|---|---|---|---|---|
| Number of expts. | 14 | 15 | 15 | 9 | |
| Based on tension | |||||
| h | 1.73 ± 0.21 | 1.79 ± 0.19 | 1.35 ± 0.22 | 1.74 ± 0.23 | — |
| pC50 | 5.28 ± 0.04 | 5.11 ± 0.07* | 5.51 ± 0.08** | 5.40 ± 0.08 | log10 |
| Based on stiffness (Y ∞) | |||||
| h | 1.78 ± 0.11 | 1.86 ± 0.16 | 1.56 ± 0.22 | 1.97 ± 0.37 | — |
| pCa50 | 5.33 ± 0.03 | 5.23 ± 0.05* | 5.52 ± 0.07** | 5.41 ± 0.09 | log10 |