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标题：HeLa cell DNA polymerase alpha is tightly associated with tryptophanyl-tRNA synthetase and diadenosine 5',5"'-P1,P4-tetraphosphate binding activities
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作者：E Rapaport ; P C Zamecnik ; E F Baril 等
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：2
页码：838-842
DOI：10.1073/pnas.78.2.838
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The purified high molecular weight form of HeLa cell DNA polymerase alpha (deoxynucleosidetriphosphate: DNA deoxynucleotidyltransferase, EC 2.7.7.7 ) was shown to associate tightly with several aminoacyl-tRNA synthetase activities. Fractionation of the high molecular weight enzyme on hexylagarose followed by gel filtration, chromatography on phosphocellulose, or polyacrylamide gel electrophoresis under nondenaturing conditions demonstrated copurification of only tryptophanyl-tRNA synthetase [L-tryptophan:tRNATrp ligase (AMP-forming), EC 6.1.1.2 ] along with DNA polymerase alpha. The high molecular weight (660,000) and low molecular weight (145,000) forms of DNA polymerase alpha were shown to possess a highly specific, noncovalent, diadenosine 5',5"'-P1,P4-tetraphosphate (Ap4A) binding activity. The dissociation constants were determined to be 16 and 22 microM, respectively, by utilization of a charcoal adsorption procedure. No high-affinity binding of ATP could be detected. These findings suggest a link between the amino acid activation process and DNA replication in mammalian cells.