文章基本信息

标题：Characterization of a rat liver factor that inhibits initiation of protein synthesis in rabbit reticulocyte lysates
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作者：Jean Delaunay ; Rajinder Singh Ranu ; Daniel H. Levin 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：1977
卷号：74
期号：6
页码：2264-2268
DOI：10.1073/pnas.74.6.2264
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Protein synthesis in rabbit reticulocytes and their lysates is regulated by heme. In heme-deficient reticulocyte lysates, protein synthesis proceeds at the initial rate for several minutes and then declines abruptly. Inhibition of protein synthesis is due to the activation of a heme-regulated translational inhibitor (HRI) which blocks the initiation of protein synthesis. Addition of the isolated HRI to hemin-supplemented lysates causes inhibition of initiation similar to that observed in heme-deficiency. HRI has been shown to be a protein kinase that specifically phosphorylates the Met-tRNAf binding factor (eIF-2). We have isolated an inhibitor (LI) of protein chain initiation from rat liver which displays properties similar to those of HRI: (i) the chromatographic behavior of LI on DEAE-Sephadex, DEAE-cellulose, and phosphocellulose is similar to that of HRI; (ii) both LI and HRI inhibit protein chain initiation in rabbit reticulocyte lysates with the same kinetics of inhibition--i.e., an initial period of synthesis for several minutes at the control rate followed by an abrupt decline in the rate of initiation; (iii) both inhibitions are prevented or reversed by eIF-2; (iv) GTP (2 mM) prevents, and ATP (2 mM) potentiates, the inhibition of protein synthesis induced by either inhibitor; (v) LI is associated with a protein kinase that also phosphorylates the 38,000-dalton subunit of elF-2. These findings indicate that a mechanism for the regulation of protein synthesis similar to that found in rabbit reticulocytes may be present in rat liver.
关键词：phosphorylation of Met-tRNA_f binding factor ; translational inhibitor