Table 1.

Rate constants used for simulation, and as initial guesses for fits

		True 1	Guess 1	Guess 2	True 2	Guess 3	Guess 4
α2	s−1	2000	1500	1500	2000	1500	1500
β2	s−1	52000	50000	50000	50000	50000	50000
α1a	s−1	6000	13000	2000	4000	2000	10000
β1a	s−1	50	50	20	80	20	50
α1b	s−1	50000	15000	80000	40000	80000	20000
β1b	s−1	150	10	300	10	30	30
k−2a	s−1	1500	6000	1000	12000	1000	20000
k+2a	M−1 s−1	2.0 × l08	1.0 × 108	1.0 × 108	0.5 × 108	1.0 × 108	1.0 × 108
k−2b	s−1	10000	5000	20000	2000	20000	1000
k+2b	M−1 s−1	4.0 × l08	1.0 × 108	1.0 × 108	5.0 × 108	4.0 × 108	2.0 × 108
k−1a	s−1	1500	6000	1000	400	1000	1000
k+1a	M−1 s−1	2.0 × 108	1.0 × 108	1.0 × 108	0.2 × 108	1.0 × 108	0.5 × 107
k−1b	s−1	10000	5000	20000	100	20000	1000
k+1b	m−1 s−1	4.0 × 108	1.0 × 108	1.0 × 108	3.0 × 108	4.0 × 108	2.0 × 108
E2	—	26	—	—	25	—	—
E1a	—	0.0083	—	—	0.02	—	—
E1b	—	0.003	—	—	0.00025	—	—
K2a	μM	7.5	—	—	240	—	—
K2b	μM	25	—	—	4	—	—
K1a	μM	7.5	—	—	20	—	—
Klb	μM	25	—	—	0.333	—	—

Values for rate constants are shown in the first 14 rows. The last seven rows show, for the true rate constants, the corresponding values of the equilibrium constants. True 1: the true values for rate constants for scheme 1 (Fig. 1), that were used for simulation of experiments shown in Figs 2–10. Guess 1: the initial guesses used for fitting in Fig. 2 (the two sites are similar in the guesses). Guess 2: initial guess with the two sites very different as used for the results in Figs 3–10. In the first 3 columns of values, the sites are assumed to be independent so the values obey the constraints defined in eqns (9) and (10). True 2: the true rates used for simulation of non-independent binding sites (Figs 14, 15, 17 and 18). Guess 3: initial guesses used for Figs 14 and 15 (similar values used for Fig. 17) Guess 4: initial guesses used for Fig. 18.