FIGURE 7.
Kinetics of mantADP release from the CENP-E·mantADP intermediate. CENP-E·mantADP was rapidly mixed in the stopped-flow instrument with ATP, and the release of mantADP was observed at 1–10 and 10–250 s. Each transient was fit to a double exponential function. A, final concentrations: 2.5 μm CENP-E, 2.5 μm mantADP, 500 μm ATP. kobs1 = 0.086 ± 0.003 s−1 with A0 = 0.046 ± 0.001, and kobs2 = 0.004 ± 0.00004 s−1 with A0 = 1.02 ± 0.004. B, final concentrations: 2.5 μm CENP-E, 1.25 μm mantADP, 500 μm ATP. kobs1 = 0.097 ± 0.005 s−1 with A0 = 0.025 ± 0.0007 and kobs2 = 0.004 ± 0.00005 s−1 with A0 = 0.55 ± 0.002. Fluorescence is expressed in arbitrary units.