  The movement of single kinesin molecules was observed while applying noisy
external forces that mimic intracellular active fluctuations. We found kinesin
accelerates under noise, especially when a large hindering load is added. The
behavior quantitatively conformed to a theoretical model that describes the
kinesin movement with simple two-state reactions. The universality of the
kinetic theory suggests that intracellular enzymes share a similar
noise-induced acceleration mechanism, i.e. active fluctuations in cells are not
just noise but are utilized to promote various physiological processes.
