MOLECULAR WEIGHTS OF SOME HELA RIBOSOMAL RNAS

The molecular weights of HeLa ribosomal RNA's, determined by sedimentation equilibrium at pH 7.0, were found to be: 45 s RNA, 4 to 4.5 × 106 daltons; 32 s RNA, 2.4 × 106 daltons; 28 s RNA, 1.9 × 106 daltons; 18 s RNA, 0.71 × 106 daltons. These values imply a non-conservative transition from the 45 s precursor to the mature 18 and 28 s ribosomal RNA's. © 1969.