Figure 2.

ATPase activity of the chimeras and wild-type H⁺,K⁺-ATPase. The assay was performed at 37°C with ≈1 μg of protein in the presence of 0.2 mM EDTA/0.1 mM EGTA/1.2 mM MgCl₂/50 mM Tris-acetic acid, pH 6.0/3.0 mM KCl/10 μM ATP. The ATPase activity determined was corrected for that of the mock. Shown are mean values ± SE of two to four enzyme preparations.