Actin filaments were incubated in F buffer containing 1 mM ADP and 0.1 mM ATP for 5 min or in F buffer containing 1 mM ADP for 30 min prior to the addition of cofilin. Filaments under the latter condition were shorter than those under the former condition and were apparently in the process of spontaneous depolymerization.
Each mean and SD were calculated from 423 to 446 data.