Figure 7. Relationship between tension and ATPase activity in reconstituted rat cardiac muscle fibres from PTU-treated rat hearts.

Simultaneous measurement of tension and ATPase activity at different pCa are as described in the Methods. Averaged data from several experiments were fitted using a linear regression analysis. Departure from linearity was found to be non-significant in all cases. WT-cTnT + cTnI + cTnC reconstituted muscle fibres (○), R² = 0.95; cTnT_E162DEL + cTnI + cTnC reconstituted muscle fibres (•), R² = 0.96; and cTnT_K211DEL + cTnI + cTnC reconstituted muscle fibres (▵), R² = 0.97. Comparison of mean slope values (tension cost) between reconstituted muscle fibres from normal and PTU-treated hearts are shown in Fig. 8A. Number of determinations is at least eight for each.