Subramanian A R, Davis B D
Proc Natl Acad Sci U S A. 1971 Oct;68(10):2453-7. doi: 10.1073/pnas.68.10.2453.
The runoff of a mixture of "heavy" and "light" polysomes has been reported to yield hybrid ribosomes, of intermediate density. However, we found that the dissociation of free heavy ribosomes as they advance in a sucrose gradient causes a serious artefact in the demonstration of hybrid ribosomes. This artefact is eliminated by fixation with glutaraldehyde before sedimentation. Formation of hybrid ribosomes can then be demonstrated, but it is equally complete whether the heavy and light preparations are mixed before or after runoff. Hence, free ribosomes exchange subunits rapidly in extracts. The previously reported exchange thus does not provide evidence for formation of free subunits during runoff.
据报道，“重”、“轻”多核糖体混合物的流出会产生中等密度的杂交核糖体。然而，我们发现游离重核糖体在蔗糖梯度中前进时的解离，在杂交核糖体的展示中会导致严重的假象。通过在沉降前用戊二醛固定可以消除这种假象。然后可以证明杂交核糖体的形成，但无论重、轻制剂在流出前还是流出后混合，形成都是同样完全的。因此，游离核糖体在提取物中迅速交换亚基。因此，先前报道的交换并不能为流出过程中游离亚基的形成提供证据。
