Detachment of molecular motors under tangential loading

We introduce a general framework to study the processivity of molecular mot ors moving along a polar lament and discuss the average time spent attached to the lament as a function of a tangentially applied load. Our study of s pecific models suggests that the attachment time of a motor decreases with increasing ATP concentration and that double-headed motors such as kinesins lose their processivity under forcing conditions while processive single-h eaded motors are less sensitive to tangential forcing.