Table 1. Comparison between key... | Rockefeller University Press

Table 1.

Comparison between key contractile variables for a model with one and three myosin-binding sites per target zone on the actin filament at a cross-bridge stiffness of 2.8 pN/nm and 30°C for fast mammalian skeletal muscle

Variable	Experimental (muscle cells)	Three-site model	One-site model	Ratio (three site/one site)
Sliding velocity (nm/s)	13,000–18,000 nm/s (Ranatunga, 1984; Månsson et al., 1989; Asmussen et al., 1994; Thedinga et al., 1999)	13,800	14,300	0.965
Maximum isometric force	400 kPa (Westerblad et al., 1997) translates into 500 kPa for myofibrils	390 kPa 2.08 pN/head	109 kPa 0.74 pN/head	2.81
Isometric ATPase	8–35 s⁻¹ (Reggiani et al., 1997; He et al., 1999; Sun et al., 2001)	11.7 s⁻¹	5.0 s⁻¹	2.34
Fraction of attached cross-bridges (isometric)	0.33 ± 0.05 (Linari et al., 2007) 0.4 (Koubassova et al., 2008)	0.31	0.108	2.87
Average cross-bridge strain	>5 nm (Linari et al., 2007)	2.4 nm	2.46 nm	0.976

Variable	Experimental (muscle cells)	Three-site model	One-site model	Ratio (three site/one site)
Sliding velocity (nm/s)	13,000–18,000 nm/s (Ranatunga, 1984; Månsson et al., 1989; Asmussen et al., 1994; Thedinga et al., 1999)	13,800	14,300	0.965
Maximum isometric force	400 kPa (Westerblad et al., 1997) translates into 500 kPa for myofibrils	390 kPa 2.08 pN/head	109 kPa 0.74 pN/head	2.81
Isometric ATPase	8–35 s⁻¹ (Reggiani et al., 1997; He et al., 1999; Sun et al., 2001)	11.7 s⁻¹	5.0 s⁻¹	2.34
Fraction of attached cross-bridges (isometric)	0.33 ± 0.05 (Linari et al., 2007) 0.4 (Koubassova et al., 2008)	0.31	0.108	2.87
Average cross-bridge strain	>5 nm (Linari et al., 2007)	2.4 nm	2.46 nm	0.976