Figure 3.

Kinetic analysis of kinesin steps. (a) Kinetic pathway of kinesin steps. Forward steps, backward steps, or detachments occur by passing through a sequence of load-independent transitions (state 1 to state 2) and a load-dependent transition (state 2 to forward step, backward step or detachment). (b) Load-dependence of rate constants (mean±s.e.m) for the forward steps (k_f, blue), backward steps (k_b, red) and detachments (k_d, green) at different [ATP]s. The lines are best fits to equation (1). All kinetic parameters determined are listed in Table 1. The dotted lines in the right ([ATP_lim]) are the data from the left ([ATP_sat]) and are included for comparison.