. Author manuscript; available in PMC: 2014 Apr 1.

Published in final edited form as: Biochim Biophys Acta. 2012 Aug 23;1833(4):804–811. doi: 10.1016/j.bbamcr.2012.08.011

Table 1.

Average single myofibril parameters.

	maximum tension (mN/mm²)	k_ACT (s⁻¹)	k_TR (s⁻¹)	k_LIN (s⁻¹)	t_LIN (ms)	k_EXP (s⁻¹)
WT	110 ± 10	3.26 ± 0.16	4.07 ± 0.16	2.44 ± 0.18	130 ± 10	31 ± 2.0
HM	80 ± 10 ^*	2.64 ± 0.24 ^*	3.30 ± 0.27 ^*	2.40 ± 0.14	120 ± 10	34 ± 4.7

Activation/relaxation tension kinetic parameters were obtained in wild type (WT) and homozygous mutant (HM) single myofibril preparations by rapid solution switching. Ca²⁺ activation was mono-exponential (k_ACT), while relaxation was biphasic characterized by a slow linear relaxation phase (rate, k_LIN; duration, t_LIN) followed by rapid exponential tension decline (k_EXP) towards baseline. When tension development had reached steady state (cf. Figure 5), a rapid release-restretch maneuver was employed to measure exponential tension redevelopment (k_TR). HM myofibrils displayed reduced maximum tension development and reduced activation kinetics.

Values are expressed as means ± S.E.M.

P<0.05