Figure 3. Effect of preincubation with MgADP.

The α₃β₃γ or α₃β₃γε (5 µM) was incubated with the indicated concentrations of MgADP for more than 10 min at 25° C. Residual ATPase activity was measured in the presence of 2 mM ATP. The initial rate (2–4 s after the start of the reaction) was measured, and the values relative to the control without incubation with MgADP (82.9 ± 5.4 s^-1 and 88.6 ± 3.6 s^-1 for α₃β₃γ and α₃β₃γε, respectively) are plotted. Closed and open circles represent α₃β₃γ and α₃β₃γε, respectively. Error bars represent standard errors.