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:1974
卷号:71
期号:1
页码:68-72
DOI:10.1073/pnas.71.1.68
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:Initiation factors, extracted from ribosomal particles by high salt, are usually tested for with the extracted ribosomes. However, it is theoretically possible that such tests may respond not only to factors (i.e., proteins that join and leave a ribosome during its cycle), but also to true ribosomal proteins that may have been extracted. We have eliminated this circularity by tests with purified polysomes, which have not been extracted with high salt; the polysomes are deficient in initiation factors because they have been largely separated from the native subunits. Tests with both systems, applied to extracts of different classes of particles, suggest that high salt does extract both initiation factors and essential ribosomal proteins. Extracts of native subunits contain both, and stimulate both systems; while, in the presence of these extracts, the extracts of polysomes further stimulate only the extracted ribosomes.