  We examine the dependence of the physical quantities of the rotatory
molecular motor, such as the rotation velocity and the proton translocation
rate, on the chemical reaction rate using the model based only on diffusion
process. A peculiar behavior of proton translocation is found and the energy
transduction efficiency of the motor protein is enhanced by this behavior. We
give a natural explanation that this behavior is universal when certain
inequalities between chemical reaction rates hold. That may give a clue to
examine whether the motion of the molecular motor is dominated by diffusion
process or not.
