The giant acceleration (GA) of diffusion is a universal phenomenon predicted by the theoretical analysis given by Reimann et al. [Phys. Rev. Lett. 87, 010602 (2001)]. Here we apply the theory of the GA of diffusion to a single-molecule experiment on a rotary motor protein, F-1, which is a component of FoF1 adenosine triphosphate synthase. We discuss the energetic properties of F-1 and identify a high energy barrier of the rotary potential to be 20k(B)T, with the condition that the adenosine diphosphates are tightly bound to the F-1 catalytic sites. To conclude, the GA of diffusion is useful for measuring energy barriers in nonequilibrium and single-molecule experiments.