SummaryRibosomes were prepared from normal human granulocytes, acute and chronic leukemias and rat liver. These preparations were analyzed for polyribosome (PRS) profile by means of sucrose density gradient centrifugation. None of the leukemic cell preparations had as high a proportion of PRS as did rat liver. Normal granulocytes and chronic granulocytic leukemic (CGL) cells had a greater fraction of PRS than did acute granulocytic (AGL) or chronic lymphocytic leukemic (CLL) cells. Most of the AGL and CLL particles were ribosomal subunits, monomer s, and dimers. With 30′ of uridine-3H labeling of all types of leukemic cells, the highest specific activity was in the subunits and PRS regions with low specific activity in the monomer-dimer regions. The data suggests that the monomers and dimers are not intermediates for the formation of PRS.
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