TABLE 1.

Kinetic parameters of V₁-ATPases and F₁-ATPases from different sources

Protein/measurement temperature	kon(ATP)a	kon(ATP) (3 × Vmax/Km)a	τ1/τ2a	Ref.
	m−1 s−1	m−1 s−1	ms
EhV1d
26 ± 1 °C	(2.3 ± 0.03) × 106	(2.2 ± 0.4) × 106	2.6 ± 0.1/0.5 ± 0.02e	This work
TtV1
23 °C	1.5 × 106	0.84 × 106	2.8/2.8	11
24 ± 1 °C		1.39 × 106		21
TF1
23 °C	3.0 × 107	2.6 × 107	1.6/0.71	13
25 ± 1 °C			1.34/0.29	20
25 ± 1 °C		2.2 × 107		27
EF1
23 °C	4.7 × 107	6.4 × 107	0.41/0.29	15

^a The second-order binding rate constant for ATP (k_on(ATP)) was determined from the distribution of the duration of the ATP-waiting pause.

^b The second-order binding rate constant for ATP (k_on(ATP)) was determined from 3 × V_max/K_m.

^c Time constants were determined from the distribution of the duration of the catalytic pause, which corresponds to ATP cleavage and either ADP or phosphate release (or both).

^d The values are the mean ± S.E. of fitting.

^e The values were obtained at 40 mm ATP.