Rate of addition of ATP-G-actin

The rate of addition of ATP-G-actin is much (10X) faster at the plus end than the minus end, whereas the rate of dissociation is similar. In the filament ATP hydrolyses to ADP-Pi and Pi is released slowly giving rise to a filament containing ATP-actin, ADP-Pi-actin and ADP-actin. ATP-actin is added preferentially at the plus end while ADP-actin disassembles at the minus end, giving rise to treadmilling of subunits. [Note that Cc = koff/kon.]