Table 1.

Comparison of F_unb generated by unphosphorylated myosin and F_uni generated by phosphorylated myosin

	Funb, pN		Funi, pN
	Unphosphorylated Tonic Myosin	Unphosphorylated Phasic Myosin	Phosphorylated Tonic HMM Construct	Phosphorylated Phasic HMM Construct
Average force per smooth muscle myosin heavy chain molecule	0.084±0.017	0.092±0.022	1.2±0.1*	0.9±0.1*
Number of events	8	6	8	7
Average Funi (range)				0.6 (0.4–0.8)†

Values are means ± SD for unbinding force (F_unb) and means ± SE for unitary force (F_uni). Average F_unb values of unphosphorylated tonic and phasic muscle myosin molecules were measured by the single beam laser trap assay. For comparison purposes, F_uni and average F_uni values for phosphorylated heavy meromyosin (HMM) are shown, as measured with the dual-beam laser trap assay and microneedle, respectively.

^*Data from Ref. 21;

^†data from Ref. 37.