FIGURE 6.
Effect of PMCA reconstitution in C12E10/DMPC and C12E10/DOPC mixtures on the phosphorylated intermediates. PMCA was reconstituted in C12E10/DMPC (XDMPC = 0.25 and 0.7) or C12E10/DOPC (XDOPC = 0.3 and 0.6), and steady-state EP levels (A) were determined in the same experimental conditions in which the Ca2+-ATPase activity was determined in Fig. 1A, but ATP concentration was 30 μm ATP. B, Ca2+-ATPase activity was calculated from the slope of Pi released as a function of time in the same experimental condition in which steady-state EP levels were determined. The values shown are mean ± S.E. (error bars) of at least three independent experiments performed in triplicate (*, p < 0.0001 with respect to XDMPC = 0.25; **, p < 0.05 with respect to XDOPC = 0.3).