Table 2.

Estimated/fixed parameter values for rat kidney and liver mitochondrial APC

Estimated parameters
Parameter	Value (95% CI∗)		Unit
	Kidney	Liver
KT	3.98 ± 0.82	3.22 ± 0.31	mM
KP	6.26 ± 1.27	2.81 ± 0.27	mM
α1	0.28 ± 0.04	0.69 ± 0.10	unitless
α2	0.02 ± 0.01	0.33 ± 0.26	unitless
Vmax	30.66 ± 8.6	24.42 ± 2.75	nmol/min/mg protein
KCa†	1.16 ± 0.08‡	1.75 ± 0.15‡	μM
nH†	1.76 ± 0.10	1.26 ± 0.21	unitless

Fixed parameters (ion dissociation constants)§
Ions	ATP	Value	Pi	Value
H+	HATP3−	6.48	H2PO4−	6.7
K+	KATP3−	1.17	KHPO4−	0.5
Mg2+	MgATP2−	4.19	MgHPO4	1.81
Ca2+	CaATP2−	3.86	CaHPO4	1.6

^∗CI, Confidence Interval.

^†These parameters were optimized only for those data sets in which external [Ca²⁺] is perturbed.

^‡These values are close to the values reported by Aprille (1) for half-maximal activation of the APC.

^§pK values are based on temperature 25°C and ionic strength 0.1 M.