Table 1.

Kinetic and equilibrium constants for myosin V-1IQ actin-activated ATPase^a

Steady-state		ATP binding and hydrolysis		ADP binding		Actin
Vmax (+ actin)	15 s−1b	K1′k2′	0.9 μM−1⋅s−1f,g	k+5	1.2 s−1j	k−6	73 μM−1⋅s−1f
Vmax (+ actin)	12 s−1c	k2′	870 s−1f	k′+5	12 s−1j	k+6	0.00036 s−1f
ν0 (− actin)	0.03 s−1b	K1k2	1.6 μM−1⋅s−1g,h	k′+5	16 s−1k	K6	4.9 × 10−12 Mf
ν0 (− actin)	0.02 s−1d	k2	≥750 s−1h	k−5	4.6 μM−1⋅s−1j	k−9	4.7 μM−1⋅s−1i
KATPase	1.4 μMb,e	k+3 + k−3	>250 s−1i	k′−5	12.6 μM−1⋅s−1j	k−10	4.2 μM−1⋅s−1f
		k+3 + k−3	750 s−1h	K5	0.27 μMj	k+10	0.032 s−1f
		k4′	>250 s−1i	K′5	0.93 μMj	K10	7.6 × 10−9 Mf
				K′5	0.7 μMl

^a50 mM KCl, 1 mM MgCl₂, 1 mM EGTA, 1 mM DTT, 10 mM imidazole, pH 7.0, 25°C. 

^bSteady-state ATPase. 

^cQuench flow. 

^dSingle turnover. 

^eActin concentration at half maximum activation of steady-state ATPase. 

^fPyrene. 

^gMantATP. 

^hTryp fluorescence. 

ⁱP_i-binding protein. 

^jMantADP. 

^kPyrene, simulated 

^lmantADP titration.