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Ribonuclease activity of rat liver perchloric acid-soluble protein, a potent inhibitor of protein synthesis.

Authors: Morishita, R  Kawagoshi, A  Sawasaki, T  Madin, K  Ogasawara, T  Oka, T  Endo, Y 
Citation: Morishita R, etal., J Biol Chem. 1999 Jul 16;274(29):20688-92.
Pubmed: (View Article at PubMed) PMID:10400702

Rat liver perchloric acid-soluble protein (L-PSP) is a potent inhibitor of cell-free protein synthesis; however, its mechanism of action is not known. Here we show that the protein is a unique ribonuclease and that this activity is responsible for the inhibition of translation. The addition of perchloric acid-soluble protein to a rabbit reticulocyte cell-free system at a concentration of 6.2 microM led to an almost complete inhibition of protein synthesis. The kinetics are unlike those of hemin-controlled inhibitor, a protein that acts at the initiation step. The inhibition appears to be due to an endoribonucleolytic activity of perchloric acid-soluble protein because L-PSP directly affects mRNA template activity and induces disaggregation of the reticulocyte polysomes into 80 S ribosomes, even in the presence of cycloheximide. These effects were observed with authentic as well as recombinant L-PSP. Analysis by thin-layer chromatography of [alpha-32P]UTP-labeled mRNA incubated with the protein showed production of the ribonucleoside 3'-monophosphates Ap, Gp, Up, and Cp, providing direct evidence that the protein is an endoribonuclease. When either 5'- or 3'-32P-labeled 5 S rRNA was the substrate, L-PSP cleaved phosphodiester bonds only in the single-stranded regions of the molecule.


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RGD Object Information
RGD ID: 9685547
Created: 2015-01-19
Species: All species
Last Modified: 2015-01-19
Status: ACTIVE


RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.