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. 2015 Jun 24;309(5):F434–F446. doi: 10.1152/ajprenal.00539.2014

Table 3.

C50 values for the 1:1 and 2:2 H+(Na+)-K+(NH4+)-ATPase model data in Fig. 2

1:1-per-ATP model
2:2-per-ATP model
C50, mM R2 C50, mM R2
Experiment 1 (K+ concentration varies) 0.240 ± 0.000 1.00 0.228 ± 0.000 1.00
Experiment 2 (NH4+ concentration varies) 0.915 ± 0.003 0.996 0.807 ± 0.005 1.00
Experiment 3 (Na+ concentration varies; NH4+-free bath) 3.25 ± 0.00 0.999 4.25 ± 0.01 0.993
Experiment 4 (Na+ concentration varies, K+-free bath) 2.66 ± 0.01 0.974 4.12 ± 0.01 0.991

C50, half-maximal ion concentration. Each data set (i.e., lines that fit circles and squares in Fig. 2, A and B for the 1:1 model and C and D for 2:2 model) was fitted using Eq. 38 [Hill coefficient (n) = 1 for the 1:1 model and n = 2 for the 2:2 model] to obtain C50 (see Normalization methods in the appendix).