Table 1.

Estimated parameter values in the models of mitochondrial 3Na⁺-1Ca²⁺ antiporter

Parameter	Values for Model 1		Values for Model 2		Values for Model 3		Reference
	Case 1(K0Ne = K0Nx, K0Ce = K0Cx)	Case 2(K0Ne ≠ K0Nx, K0Ce ≠ K0Cx)	Case 1(K0Ne = K0Nx, K0Ce = K0Cx)	Case 2(K0Ne ≠ K0Nx, K0Ce ≠ K0Cx)	Case 1(K0Ne = K0Nx, K0Ce = K0Cx)	Case 2(K0Ne ≠ K0Nx, K0Ce ≠ K0Cx)
ka0	4.9, 5.56.80, 13.7	4.78, 5.46.20, 12.10	5.8, 5.87.8, 14.2	5.55, 5.737.2, 12.5	5.2, 5.657.2, 13.8	4.91, 5.66.9, 13.2	r1, r2r3, r4
kb0	4.9, 5.56.80, 13.7	4.76, 5.375.70, 14.23	5.8, 5.87.8, 14.2	5.66, 5.858.5, 13.2	5.2, 5.657.2, 13.8	5.07, 5.88.55, 13.04	r1, r2r3, r4
KNe0	9.14 × 10−32.2 × 10−31.03 × 10−3	8.83 × 10−32.10 × 10−31.02 × 10−3	4.8 × 10−31.4 × 10−30.66 × 10−3	5.18 × 10−31.36 × 10−30.82 × 10−3	6.51 × 10−31.90 × 10−30.90 × 10−3	5.87 × 10−31.80 × 10−30.89 × 10−3	r1, r2r3r4
KNx0	9.14 × 10−32.2 × 10−31.03 × 10−3	8.82 × 10−31.90 × 10−31.01 × 10−3	4.8 × 10−31.4 × 10−30.66 × 10−3	4.89 × 10−31.35 × 10−30.77 × 10−3	6.51 × 10−31.90 × 10−30.90 × 10−3	5.76 × 10−31.90 × 10−30.86 × 10−3	r1, r2r3r4
KCe0	2.28 × 10−9	2.29 × 10−9	2.26 × 10−9	2.29 × 10−9	2.23 × 10−9	2.30 × 10−9	all
KCx0	2.28 × 10−9	1.89 × 10−9	2.26 × 10−9	1.89 × 10−9	2.23 × 10−9	2.10 × 10−9	all
$K_{\text{Ce}}^{\prime 0}$ (pH = 7.0)	1.36 × 10−7	1.37 × 10−7	1.38 × 10−7	1.37 × 10−7	1.35 × 10−7	1.43 × 10−7	r1, r2
$K_{\text{Ce}}^{\prime 0}$ (pH = 7.3)	1.63 × 10−6	1.70 × 10−6	1.61 × 10−6	1.70 × 10−6	1.59 × 10−6	1.71 × 10−6	r1, r2
$K_{\text{Ce}}^{\prime 0}$ (pH = 6.5)	3.98 × 10−5	3.92 × 10−5	4.16 × 10−5	3.92 × 10−5	4.03 × 10−5	4.27 × 10−5	r1, r2
$K_{\text{Ce}}^{\prime 0}$ (pH = 7.8)	1.17 × 10−3	1.22 × 10−3	1.16 × 10−3	1.22 × 10−3	1.14 × 10−3	1.23×10−3	r1, r2
$K_{\text{Ce}}^{\prime 0}$ (pH = 7.2)	4.88 × 10−7	5.08 × 10−7	4.84 × 10−7	5.08 × 10−7	4.78 × 10−7	5.11 × 10−7	r3, r4
$K_{\text{Ce}}^{\prime 0}$ (pH = 7.3)	1.63 × 10−6	1.40 × 10−6	1.61 × 10−6	1.40 × 10−6	1.59 × 10−6	1.56 × 10−6	all
KH1	6.45 × 10−8	6.47 × 10−8	6.39 × 10−8	6.47 × 10−8	6.41 × 10−8	6.38 × 10−8	all
KH2	1.39 × 10−7	1.40 × 10−7	1.39 × 10−7	1.40 × 10−7	1.39 × 10−7	1.40 × 10−7	all
αe = αx = α	0	0	0	0	0	0	all
βe = βx = β	0.5	0.5	0.5	0.5	0.5	0.5	all
Standard physiochemical/thermodynamic parameters used in the model
RT	Gas constant times temperature (298 K) in kJ mol−1					2.5775
F	Faraday's constant in kJ mol−1 mV−1					0.096484
ZCa, ZNa	Valence of Ca2+ and Na+ (unitless)					2, 1

The rate constants k_a⁰ and k_b⁰ are defined as k_a⁰ = [E]_Totk_a⁰ and k_b⁰ = [E]_Totk_b⁰. The model parameters satisfy the constraints (k_a⁰/k_b⁰)(K_Ce⁰/K_Cx⁰)(K_Nx⁰/K_Ne⁰)³ = 1 and 2(α + β) = 1. The rate constants are in the units of μmol/mg/min for Paucek and Jaburek data (7), μM/min in Cox and Matlib data (12), and % Rhod-2 signal/min for Kim and Matsuoka data (14), whereas all dissociation constants are in the units of molar (M). The references r1, r2, r3, and r4 correspond to Figs. 3 and 4, parts A–D, respectively, for each figure.