期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1971
卷号：68
期号：10
页码：2453-2457
DOI：10.1073/pnas.68.10.2453
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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.
