Polyribosome analysis on sucrose gradients produced by the freeze-thaw method.

Polyribosomes were analyzed on sucrose gradients produced by the freeze-thaw method. When gradients were formed from a starting solution containing 1 mM Mg2+ an anomalous sedimentation pattern was observed although the polyribosomal structure can be maintained at this Mg2+ concentration. The use of starting solutions containing 5--20 mM Mg2+ yielded a satisfactory sedimentation profile of polyribosomes on freeze-thaw produced gradients.