Processivity of Kinesin

Processivity is a measure of how much an enzyme can catalyze reactions without freeing its substrate. Kinesin, a motor protein that moves along microtubules, has notable processivity. It can move over a large number of subunits on the microtubule before it detaches or diffuses away. This is a rare trait for cytoskeletal motor proteins. Myosin spends most of its ATPase either weakly bound to actin or dissociated from it. It is very beneficial for kinesin to have such a high processivity so that new tubulin subunits can be added to the filament before many dissociate, which allows the microtubule to grow rapidly. This is important because microtubules are required to be dynamic and must grow to transport organelles, separate chromosomes, and sometimes facilitate in cell movement.