CHROMATOGRAPHIC ISOLATION OF 80S RIBOSOMES FROM RAT LIVER AND MOUSE PLASMA CELL TUMOR

The isolation of ribosomes from rat liver and mouse plasma cell tumor was achieved with the aid of a new adsorbent (ECTHAM-cellulose) specifically designed to permit their elution by dilute salt solutions. Microsomes, free ribosomes, and ribonucleic acid were adsorbed under conditions that allowed nearly all other components of the homogenate fraction to pass through; then microsomal lipoprotein was removed by passing a nonionic detergent through the column. A subsequent gradient of NaCl eluted ribosomes in two major peaks. In the case of rat liver, the ribosomes in these two fractions differed in sedimentation rate (83 and 77 S) and in protein:ribonucleic acid ratio (2.4 and 1.9). Both contained significantly more protein than ribosomes prepared by conventional means with deoxycholate. On rechromatography or storage at 0°, the ribosomes in the first peak shifted to the position of the second. Changes in the magnesium concentration altered the chromatographic behavior of the ribosomes. Labeling the ribonucleic acid of plasma cell tumors in vivo with [3H]uridine resulted in chromatographic fractions having different specific activities. The most firmly bound fraction contained ribonucleic acid of very high specific activity. © 1969, American Chemical Society. All rights reserved.