Table 1.

Experimentally determined KIF3 constants (35, 49–51)

—, not observed. ND, not determined.

			KIF3AB	KIF3AC	KIF3AA	KIF3BB	KIF3CC
MT association	k+1	μm−1s−1	7.0 ± 0.4	6.6 ± 0.2	11.4 ± 0.6	11.9 ± 0.1	2.1 ± 0.1
	k−1	s−1	0.8 ± 0.4	−	2.4 ± 0.9	−	0.6 ± 0.1
ADP release	k+2	s−1	39.6 ± 0.9a	42.5 ± 0.9a	77.7 ± 1.4	80.2 ± 2.5	7.6 ± 0.1
	K1/2,MT	μm	3.8 ± 0.3a	7.5 ± 0.4a	4.4 ± 0.2	4.0 ± 0.4	1.7 ± 0.1
MantATP binding	k+3	μm−1s−1	7.5 ± 0.5	11.0 ± 0.6	16.0 ± 0.5	7.5 ± 0.5	0.68 ± 0.04
	k−3	s−1	46.1 ± 5.5	21.4 ± 7.2	10.5 ± 5.1	46.1 ± 5.5	7.7 ± 0.4
ATP-isomerization	k+4	s−1	84.0 ± 1.9	81.0 ± 1.0	ND	ND	ND
ATP hydrolysis	k+5	s−1	33.0 ± 2.5b	69.1 ± 1.2	ND	ND	ND
	Amax		3.0 ± 0.2 per site	0.77 ± 0.02 per site	ND	ND	ND
Steady-state	kcat	s−1	31.7 ± 1.2	21.5 ± 0.3	34.7 ± 0.5	32.1 ± 0.4	1.1 ± 0.02
	Km,ATP	μm	122.9 ± 15.0	138.1 ± 12.8	47.7 ± 0.1	71.4 ± 4.0	4.8 ± 0.5
	K1/2,MT	μm	0.14 ± 0.01	0.23 ± 0.03	0.19 ± 0.002	0.14 ± 0.005	0.04 ± 0.007
Single molecule velocity	−	nm/s	246.2 ± 11.1	186.5 ± 5.6	293.2 ± 4.2	327.6 ± 7.2	7.5 ± 0.4

^a KIF3 constants determined from the experimental data presented in this study.

^b Predicted to be much higher at ∼80 s⁻¹ (4, 43, 52).