Figure 4.

Normalized pCa‐force relationship in skinned cardiac muscle fibers. The Ca²⁺ dependence of force development was measured in each preparation after whole troponin (Tn) displacement and reconstitution at pH 7.0 and pH 6.5. The maximal force recovery was also evaluated and no significant difference was observed at pH 7.0 between fibers containing wild‐type human cardiac troponin T (HCTnT‐WT) and HCTnT‐R139H (57.4 ± 1.8 vs. 58.9 ± 4.7), respectively. However, a difference in maximal force recovery was observed at pH 6.5 between HCTnT‐WT and HCTnT‐R139H (53.9 ± 2.6 vs. 43.8 ± 2.7), respectively. Data in each experiment are the average of 5 experiments and expressed as mean ± S.E. *=p < 0.05 compared to the HCTnT‐WT.