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：1981
卷号：78
期号：11
页码：6766-6770
DOI：10.1073/pnas.78.11.6766
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Incubation of O6-[3H]ethylguanine-containing DNA with a rat liver chromatin fraction resulted in a decrease in the O6-ethylguanine content of the DNA. Analysis of the products of this reaction showed that the ethyl group had been transferred from the O6-ethylguanine to a protein acceptor. When the incubation mixture was separated on a cesium chloride gradient, the radioactivity removed from O6-ethylguanine appeared in a low-density band. This material has been isolated and subjected to trypsin digestion and high-pressure liquid chromatography analysis; it was sensitive to trypsin and the digest contained new high-pressure liquid chromatography peaks characteristic of oligopeptides. Radioactive peaks from the trypsin digestion have been digested further to the amino acid level and have been shown to contain S-[3H]ethylcysteine. Thus, we conclude that the repair activity in rat liver chromatin removes the ethyl group from O6-ethylguanine and transfers it to a cysteine moiety contained in an acceptor protein.
