Tropomyosin Period 3 Is Essential for Enhancement of Isometric Tension in Thin Filament-Reconstituted Bovine Myocardium

Table 1

Resting tension and stiffness. The fibers were relaxed at 0°C in the relaxing solution that contains 40 mM BDM. Tension at pCa7.0 was measured at 25°C as the incremental tension from the relaxed level. All the measured parameters were normalized to 𝑇_ac, the active tension of the actin filament reconstituted fibers at 25°C. Compared to the nfTm control, all P values are > .05, hence there are no significant differences from nfTm in three parameters measured.

	nfTm (control)	▵2Tm	▵3Tm	Acetyl Tm^†	Units
Number of expts.	17	18	18	8
Tension at pCa 7	0.065 ± 0.113	0.109 ± 0.033	0.196 ± 0.047	0.168 ± 0.052	𝑇ac
Stiffness at pCa 7	0.044 ± 0.015	0.039 ± 0.004	0.040 ± 0.004	0.038 ± 0.011	𝑇ac
Stiffness at relaxation	0.055 ± 0.022	0.049 ± 0.005	0.044 ± 0.005	0.048 ± 0.015	𝑇ac

^†Data obtained together with [13] but were not published.