Table 2.
Organellar function and enzyme activities
| Con | MLP-null | |
|---|---|---|
| Myofibrillar function | ||
| Active tension (mN mm−2) | 39 ± 3 | 18 ± 1** |
| Resting tension (mN mm−2) | 2.6 ± 0.4 | 3.1 ± 0.3 |
| pCa50 | 5.71 ± 0.02 | 5.67 ± 0.01 |
| pATP50 | 3.24 ± 0.04 | 3.29 ± 0.04 |
| Mitochondrial function | ||
| V0 (μmol O2 min−1 (g dry wt−1)) | 6.0 ± 0.4 | 4.3 ± 0.2* |
| Vmax (μmol O2 min−1 (g dry wt−1)) | 22.5 ± 1.1 | 23.3 ± 1.0 |
| Acceptor control ratio | 3.9 ± 0.3 | 5.8 ± 0.3** |
| Apparent Km(ADP) | 270 ± 34 | 175 ± 15* |
| Enzyme activities | ||
| Total CK (IU (g protein)−1) | 4226 ± 385 | 3134 ± 365 |
| CS (IU (g protein)−1) | 942 ± 112 | 923 ± 67 |
| Complex I (IU (g protein)−1) | 933 ± 47 | 898 ± 88 |
*
P < 0.05
**
P < 0.005 versus Control. pCa50, (pCa for half-maximal active tension); pATP50, (pATP for half-maximal rigor tension); CK, creatine kinase; CS, citrate synthase.