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：1979
卷号：76
期号：7
页码：3107-3110
DOI：10.1073/pnas.76.7.3107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The ATP-dependent proteolytic cell-free system from reticulocytes has been resolved into three components, each of which is absolutely required for acid solubilization of 125I-labeled bovine serum albumin radioactivity. In addition to the previously reported heat-stable polypeptide [Ciechanover, A., Hod, Y. & Hershko, A. (1978) Biochem. Biophys. Res Commun. 81, 1100-1105], we now describe a protein of high molecular weight (approximately 450,000) that is labile at 42 degrees C. The extremely heat-labile factors is remarkably stabilized by ATP. GTP and CTP, which do not stimulate protolysis, do not stabilize this factor. Adenylate nucleotides such as ADP or the nonhydrolyzable beta,gamma imido or methylene analogues of ATP cause stabilization although they do not activate proteolysis. A third protein component of the protease system, stable at 42 degrees C, has been separated from the heat-labile species by salt precipitation. All three components are required with ATP for proteolytic activity, but thus far only the heat-labile factor has been shown to interact directly with ATP.
