The increase in the incorporation of amino acids into protein in vitro by preparations obtained from protein-fed rats as compared with preparations obtained from carbohydrate-fed rats has been described previously. After molecular sieving through Sephadex G-25 of cell-free preparations, the difference in incorporating activity between the two types of rats was diminished in systems containing ATP, phosphoenolpyruvate, pyruvate kinase, GTP, and a mixture of amino acids. When, after molecular sieving, a mitochondrial (15,000 g) supernatant was incubated for 4 min at 35°C the polysomal pattern of the preparations was unchanged. In the presence of ATP, phosphoenolpyruvate, and pyruvate kinase the polysomal incorporating activity was low and the polysomal pattern was only slightly changed. Addition of GTP increased the activity markedly, and a more pronounced activity was observed when a mixture of amino acids was added as well. As the amino acid incorporation ability increased, monosomes were formed from the polyribosomes. The activity of the polyribosomes was severalfold higher than that of non-Sephadex-treated preparations, indicating an activation of polysomal aggregates which under the usually applied conditions of incubation and prior to molecular sieving show little or insignificant activity. It was possible to activate polyribosomes from carbohydrate-fed and protein-fed rats to almost the same extent.
Article| October 01 1969
ACTIVATION IN VITRO OF RAT LIVER POLYRIBOSOMES
Alexandra von der Decke
From the Wenner-Gren Institute for Experimental Biology, Stockholm, Sweden
Received: March 25 1969
Revision Received: May 01 1969
Online Issn: 1540-8140
Print Issn: 0021-9525
Copyright © 1969 by The Rockefeller University Press.
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Alexandra von der Decke; ACTIVATION IN VITRO OF RAT LIVER POLYRIBOSOMES . J Cell Biol 1 October 1969; 43 (1): 138–147. doi: https://doi.org/10.1083/jcb.43.1.138
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