Cosedimentation of a 120 Kilodalton Bovine Brain Polypeptide with Squid Microtubules Depends upon AMP-PNP
Bovine brain S3 supernatant was incubated with squid optic lobe microtubules (100 μg/ml) in the absence (lane a) or presence (lane b) of 5 mM AMP-PNP for 15 min at 23°C. Microtubules were pelleted, washed once with PEM-taxol-GTP buffer, resuspended in 1/40 of the original volume with the same buffer containing 5 mM ATP and 0.1 M KCl, and then assayed for movement-inducing activity.