Table 1.
Mechanical characteristics of βmys for two actins.a
| skeletal actin | cardiac actin | p< | |
|---|---|---|---|
| actin-activated myosin ATPase | |||
| Vmax (s−1) | 0.82 ± 0.07 (N = 4) | 0.76 ± 0.10 (4) | ns @ 0.05 |
| Km (μM) | 5.2 ± 1.9 | 3.7 ± 1.5 | ns @ 0.05 |
| peak in vitro motility velocity for unloaded actin | |||
| sm,max (μm s−1) | 0.20 ± 0.01 (N = 31) | 0.16 ± 0.01 (23) | 0.01 |
| isometric force (F0) in pN and dimensionless attachment rate (K) for motility data | |||
| F0 | 18.4 ± 3.7 (N = 12) | 14.3 ± 2.8 (12) | 0.01 |
| K | 10.1 ± 4.2 | 7.0 ± 4.0 | 0.01 |
| F0 corrected | 21.0 ± 2.3 (12) | 15.3 ± 1.5 (12) | 0.01 |
| K corrected | 10.3 ± 4.0 | 3.7 ± 2.5 | 0.01 |
| isometric force (F0) in pN and dimensionless attachment rate (K) for Qdot assay motility data | |||
| F0 | 38.5 ± 9.8 (N = 8) | 29.5 ± 10.5 (8) | 0.01 |
| K | 18.0 ± 0.1 | 14.0 ± 5.1 | 0.01 |
| F0 corrected | 36.5 ± 9.4 (8) | 29.1 ± 12.3 (8) | 0.01 |
| K corrected | 18.0 ± 0.1 | 12.0 ± 6.1 | 0.01 |
aAverage values and standard deviation indicated for (N) replicates. ANOVA significance under the p < heading indicates confidence level for distinguishing skeletal from cardiac actin or ns for no significant difference. F0 or K corrected refers to optimization of equations (2.2)−(2.6) using corrected cardiac actin data from equation (2.8).