Table 1.

Steady-state contractile parameters of NTG (Tm_WT) and TG (Tm_H276N) cardiac muscle fibers reconstituted with the WT Tn complex

Parameter	McTnTWT + McTnI + McTnC reconstituted into NTG TmWT cardiac muscle fibers	McTnTWT + McTnI + McTnC reconstituted into TG TmH276N cardiac muscle fibers
Tension (mN·mm−2)	49.75 ± 0.94	53.19 ± 1.82
ATPase (pmol·mm−3·s−1)	304.38 ± 9.36	274.53 ± 7.42
nH tension	2.62 ± 0.13	2.94 ± 0.26
pCa50 tension	5.65 ± 0.01	5.63 ± 0.01
Tension cost (pmol·mN−1·mm−1·s−1)	6.39 ± 0.18	5.17 ± 0.15**
ktr (s−1)	12.87 ± 0.46	13.38 ± 0.57

Isometric steady-state tension and ATPase activity were measured simultaneously, as described previously (22, 27). The Hill equation was fitted to the pCa-tension relationships to derive n_H- and pCa₅₀-tension values. Tension cost was estimated as described previously (23). k_tr was measured according to a protocol described previously (31). At least 7 determinations were done for each group. Values are reported as means ± sem

^**P < 0.01 vs. Tm_WT.