Table 3.

Model coefficients for NKCC1 transport under hypertonic conditions

	Simulation
	1	2	3
Number of transporters	1,000	2,100–2,300	3,000
ki	0.5	2.4–2.5	0.5
ko	1	1	1
fi	0.7	0.2	0.3
fo	10	6–10	2–4
gi	8	2.7–3	2
go	2–4	2–4	2
K1	5–7	4	5
K2	25–30	22–24	30
K3	170–200	180–220	200
K4	9–11	7–9	7
K5	10–160	14–24	40–160
K6	1–19	1–11	4–19
K7	40–160	5–9	10–160
K8(*)	5–40	100–200	19–195
K+ influx/K+ efflux	1.7	1.6	1.8
K+ influx/Na+ influx	3.1–4.9	3.0–3.2	2.1–3.5
K+ efflux ([K+]o = 4)/K+ efflux ([K+]o = 0)	2.5–2.6	3.0–3.2	2.1

In this series of simulations, we varied 13 of the 15 kinetic parameters. Translocation rate constants ko was set at 1. ^(*)K8 was mathematically derived based on thermodynamic constraints (see materials and methods, Theoretical Considerations, Fig. 3). We varied the number of transporters (1,000–8,000), the remaining translocation rate constants ki (0.1–3), fo (1–10), fi (0.1–1), gi (1–10), go (1–10); and the binding affinities (mM) as follows: K1 (1–19); K2 (20–30); K3 (10–200); K4 (1–30); K5 (10–190); K6 (1–20); and K7 (1–10 or 10–160). Reported parameter values were obtained using Eqs. 11 and 12 for conditions were 1) compatible with Table 2; 2) K⁺ influx > Na⁺ influx; 3) K⁺ efflux ([K⁺]o = 4) > K⁺ efflux ([K⁺]o = 0); and 4) fit the data of Fig. 8. Note that when the products of ion concentrations inside and outside are equal (Nai × Ki × Cli² = Nao × Ko × Clo²), the simulation resulted in no net flux.