Skip to main content
NCBI home page
Biochemical Journal logoLink to Biochemical Journal
. 1965 Nov;97(2):422–431. doi: 10.1042/bj0970422

Studies on the protein-synthesizing activity of the ribosomes of rat liver. The activity of free polysomes

P N Campbell 1, Guldborg Serck-Hanssen 1,*, Elizabeth Lowe 1
PMCID: PMC1264657  PMID: 5880015

Abstract

1. The activities of microsome fractions from the liver of adult and 5-day-old rats for the incorporation of [14C]phenylalanine into protein were similar in the presence and absence of polyuridylic acid. 2. The activity of a light-microsome fraction from adult liver was greater than that of a heavy-microsome fraction, and the light-microsome fraction was also more markedly stimulated by the presence of polyuridylic acid. 3. The light-microsome fraction, when analysed by density-gradient centrifugation, contained a higher ratio of free ribosomes to bound ribosomes, whereas the reverse was true for the heavy-microsome fraction. Similar results were obtained for liver from adult and 5-day-old rats. 4. When the light-microsome fraction was incubated under conditions in which amino acid was incorporated into protein there was only a small increase in the ratio of free to bound ribosomes. When such a fraction was incubated with [14C]leucine and was then subjected to density-gradient centrifugation the fraction with the highest specific activity based on RNA had a density between that of the bound and free ribosomes. Treatment of the incubated fraction with ribonuclease shifted the radioactivity towards the free ribosome peak. These properties are consistent with the presence of active free polysomes. Such a component appeared also to be present when the heavy-microsome fraction was incubated under similar conditions. 5. The effect of the presence of polyuridylic acid on the incorporation of [14C]phenylalanine by the light-microsome fractions from liver of adult and 5-day-old rats was greatest in the region of the free ribosomes, but it is probable that some small polysomes containing polyuridylic acid are formed. 6. Polyuridylic acid also stimulated the bound ribosomes to a small extent when the heavy-microsome fraction from the liver of young rats was incubated with [14C]phenylalanine. 7. The results are discussed in terms of the various morphological constituents in liver now known to play a role in the synthesis of protein for export and for the internal activity of the cell.

Full text

PDF
422

Images in this article

430-1PLATE 1
on p.430-1

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. BLOEMENDAL H., BONT W. S., BENEDETTI E. L. PREPARATION OF RAT-LIVER POLYSOMES WITHOUT THE UTILIZATION OF DETERGENT. Biochim Biophys Acta. 1964 May 18;87:177–180. doi: 10.1016/0926-6550(64)90064-7. [DOI] [PubMed] [Google Scholar]
  2. Campbell P. N., Cooper C., Hicks M. Studies on the role of the morphological constituents of the microsome fraction from rat liver in protein synthesis. Biochem J. 1964 Aug;92(2):225–234. doi: 10.1042/bj0920225. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. HENSHAW E. C., BOJARSKI T. B., HIATT H. H. PROTEIN SYNTHESIS BY FREE AND BOUND RAT LIVER RIBOSOMES IN VIVO AND IN VITRO. J Mol Biol. 1963 Aug;7:122–129. doi: 10.1016/s0022-2836(63)80041-8. [DOI] [PubMed] [Google Scholar]
  4. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  5. Munro A. J., Jackson R. J., Korner A. Studies on the nature of polysomes. Biochem J. 1964 Aug;92(2):289–299. doi: 10.1042/bj0920289. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. PORTER K. R. Electron microscopy of basophilic components of cytoplasm. J Histochem Cytochem. 1954 Sep;2(5):346–375. doi: 10.1177/2.5.346. [DOI] [PubMed] [Google Scholar]
  7. RENDI R., HULTIN T. Preparation and amino acid incorporating ability of ribonucleoprotein-particles from different tissues of the rat. Exp Cell Res. 1960 Mar;19:253–266. doi: 10.1016/0014-4827(60)90006-9. [DOI] [PubMed] [Google Scholar]
  8. SARGENT J. R., CAMPBELL P. N. THE SEQUENTIAL SYNTHESIS OF THE POLYPEPTIDE CHAIN OF SERUM ALBUMIN BY THE MICROSOME FRACTION OF RAT LIVER. Biochem J. 1965 Jul;96:134–146. doi: 10.1042/bj0960134. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. SLAUTTERBACK D. B., FAWCETT D. W. The development of the cnidoblasts of Hydra; an electron microscope study of cell differentiation. J Biophys Biochem Cytol. 1959 May 25;5(3):441–452. doi: 10.1083/jcb.5.3.441. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Von Der Decken A., Campbell P. N. Studies on the synthesis of serum albumin by ribonucleoprotein particles isolated from rat liver. Biochem J. 1962 Sep;84(3):449–455. doi: 10.1042/bj0840449. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. WEBB T. E., BLOBEL G., POTTER V. R. POLYRIBOSOMES IN RAT TISSUES. I. A STUDY OF IN VIVO PATTERNS IN LIVER AND HEPATOMAS. Cancer Res. 1964 Aug;24:1229–1237. [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES