Composition of mammalian ribosomal subunits: a re-evaluation.
A method for preparation of highly active mammalian ribosomal subunits is described, which yields 60S subunits containing no more than 33% protein. It is suggested that the composition of these subunits corresponds closely to that of Escherichia coli 50S subunits. Data on the composition of bacterial and mammalian ribosomal subunits recovered from CsCl are given. It is shown that the commonly employed assumptions about the relationship between the buoyant density of a particle in CsCl and its protein content are in error. The composition of ribosomal subunits cannot ordinarily be calculated from the buoyant density in CsCl.
D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis*; D002499:Centrifugation, Density Gradient; D004926:Escherichia coli / Q000032:analysis / Q000166:cytology; D005260:Female; D006367:HeLa Cells / Q000032:analysis; D006801:Humans; D008099:Liver / Q000032:analysis; D051379:Mice; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis*; D012335:RNA, Ribosomal / Q000032:analysis; D012270:Ribosomes / Q000032:analysis*
D001426:Bacterial Proteins; D011506:Proteins; D012335:RNA, Ribosomal