Figure 2.

Effect of Na⁺ _o on the membrane potential dependence of K _0.5 for Na,K -pump current activation with RD enzyme. K _0.5 values were obtained by fitting a Hill equation to data similar to those shown in Fig. 1 C and data taken from Argüello et al. 1996. The best-fit functions (solid curves) for K _0.5 vs. V _M in the presence of 0 (•) and 148 (○) mM Na⁺ _o were calculated with and , respectively. Fitting parameters are given in the text.