Advertisement

The Journal of Membrane Biology

, Volume 36, Issue 1, pp 233–251 | Cite as

Uracil transport inSaccharomyces cerevisiae

  • R. Jund
  • M. R. Chevallier
  • F. Lacroute
Article

Summary

Uracil transport inSaccharomyces cerevisiae is mediated by a specific “permease” which does not recognize other pyrimidines such as uridine, cytosine, thymine, 2-hydroxypyrimidine or 5-amino-uracil; hypoxanthine and 6-amino-uracil slightly inhibit the uptake of uracil in a strain lacking cytosine permease activity. Wild type cells concentrate extracellular uracil before its transformation into UMP and subsequent incorporation into nucleic acids. A strain lacking UMP pyrophosphorylase and uridine ribohydrolase (strainfur 1–8 rh, in which the endogenous production as well as the utilization of uracil are lacking) is able to concentrate14C-2 uracil from the medium. At the same time no other14C-2 labelled compound could be detected in this strain, thus suggesting that the uptake of uracil in yeast occurs by active transport which is not coupled to the UMP pyrophosphorylase. The optimal pH of uracil uptake in standard growth conditions was 4.3. It was deduced from experiments performed on strainfur 1–8 rh with3H-5 and14C-2 uracil that the intracellular pool of uracil is recycled once the steady-state has been reached. First order kinetics with similar rate constants were observed for uracil efflux in strainfur 1–8 rh (k min−1=0.75±0.08) as well as in the strain lacking uracil permease,fur 1–8 rh fur 4–6 (k min−1=0.60±0.08). The intracellular pool of14C-2 uracil can be chased in strainfur 1–8 rh by addition of3H uracil without inducing a large initial acceleration of the exit rate (the rate constant remained at 0.60). 2-4-dinitrophenol inhibits the uptake of uracil but also reduces the efflux of uracil in strainfur 1–8 rh fur 4–6. These data and the comparison with cytosine transport in the same organism support the hypothesis that, whereas uracil uptake is a “permease” mediated active transport, the efflux of uracil does not involve the uracil uptake “permease”. A coefficient of permeability of 7.4×10−7 cm sec−1 was calculated for uracil.

Keywords

Cytosine Active Transport Uracil Uridine Thymine 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Berlin, R.D., Stadtman, E.R. 1966. A possible role of purine nucleotide pyrophosphorylase of purine byBacillus subtilis.J. Biol. Chem. 211:2679Google Scholar
  2. 2.
    Burman, S. Roy, Visser, D.W. 1975. Transport of purines and deoxyadenosine inEscherichia coli.J. Biol. Chem. 250:9270PubMedGoogle Scholar
  3. 3.
    Carter, C.E. 1957. Partial purification of a nonphosphorylytic uridine nucleosidase from yeast.J. Am. Chem. Soc. 73:1508Google Scholar
  4. 4.
    Chevallier, M.R., Jund, R., Lacroute, F. 1975. Cytosine permeation inSaccharomyces cerevisiae. Characterization of the cytosine permease.J. Bacteriol. 122:629PubMedGoogle Scholar
  5. 5.
    Cuppoletti, J., Segel, I.H. 1974. Transinhibition kinetics of the sulfate transport system ofPenicillium notatum: Analysis based on an Iso Uni. Uni velocity equation.J. Membrane Biol. 17:239Google Scholar
  6. 6.
    Grenson, M. 1969. The utilization of exogenous pyrimidines and the recyclin of uridine 5′-phosphate derivatives inSaccharomyces cerevisiae, as studied by means of mutants affected in pyrimidine uptake and metabolism.Eur. J. Biochem. 11:249PubMedGoogle Scholar
  7. 7.
    Hochstadt-Ozer, J., Stadtman, E.R. 1971. The regulation of purines utilization inBacteria.J. Biol. Chem. 246:5312PubMedGoogle Scholar
  8. 8.
    Hunter, D.R., Segel, I.H. 1973. Control of the general amino acid ofPenicillium chrysogenum by transinhibition and turnover.Arch. Biochem. Biophys. 154:387PubMedGoogle Scholar
  9. 9.
    Jackman, L., Hochstadt, J. 1976. Characterization of hypoxanthine and guanine uptake into isolated membrane vesicles ofSalmonella tiphimurium.J. Bacteriol. 126:312PubMedGoogle Scholar
  10. 10.
    Jund, R., Lacroute, F. 1970. Genetic and physiological aspects of resistance to 5-fluoropyrimidines inSaccharomyces cerevisiae.J. Bacteriol. 102:607PubMedGoogle Scholar
  11. 11.
    Kepes, A. 1973. Trois classes de systèmes de transport chez les bactéries.Biochimie 55:693PubMedGoogle Scholar
  12. 12.
    Lacroute, F., Slonimski, P. 1964. Etude physiologique des mutants resistants au 5-fluorouracil chez la levure.C.R. Acad. Sci. 258:2172Google Scholar
  13. 13.
    Mortimer, R.K., Hawthorne, D.C. 1966. Genetic mapping inSaccharomyces cerevisiae.Genetics 53:165PubMedGoogle Scholar
  14. 14.
    Polak, A.M., Grenson, M. 1973. Evidence for a common transport system for cytosine, adenine and hypoxanthine inSaccharomyces cerevisiae andCandida albicans.Eur. J. Biochem. 32:276PubMedGoogle Scholar
  15. 15.
    Rader, R.L., Hochstadt, J. 1976. Involvement of membrane-associated nucleoside phosphorylases in the uptake and the base-mediated loss of the ribose moiety of nucleosides bySalmonella typhimurium membranes vesicles.J. Bacteriol. 128:291Google Scholar
  16. 16.
    Reichard, P., Skold, O. 1963. Pyrimidine synthesis and breakdown.In: Methods in Enzymology S.P. Colowick and N.O. Kaplan, Editors Vol. 6, pp. 177–197. Academic Press, New YorkGoogle Scholar
  17. 17.
    Slater, E.C. 1966. Oxydative phosphorylation.In: Comprehensive Biochemistry M. Florkin and E.H. Stotz, Editors Vol. 14, p. 327. American Elsevier, New YorkGoogle Scholar
  18. 18.
    Stein, W.D. 1967. The movement of molecules across cell membranes.In: Theoretical and Experimental Biology. J.F. Danielli, editor. Vol. 6, Chap. 4 and 6. Academic Press, New YorkGoogle Scholar
  19. 19.
    Surandra, P. Verma, Schneider, H., Smith, I.C.P. 1973. Organizational changes in phospholipid multilayers induced by uncouplers of oxydative phosphorylation: A spin label study.Arch. Biochem. Biophys. 154:400PubMedGoogle Scholar
  20. 20.
    Wilson, T.H., Kashket, E.R., Kusch, M. 1972. Energy coupling to lactose transport inE. coli.In: The Molecular Basis of Biological Transport. Academic Press, New YorkGoogle Scholar
  21. 21.
    Winkler, H.H., Wilson, T.H. 1966. The role of energy coupling in the transport of β-galactosides byE. coli.J. Biol. Chem. 241:2200PubMedGoogle Scholar

Copyright information

© Springer-Verlag New York Inc. 1977

Authors and Affiliations

  • R. Jund
    • 1
  • M. R. Chevallier
    • 1
  • F. Lacroute
    • 1
  1. 1.Laboratoire de Génétique PhysiologiqueI.B.M.C.Strasbourg CedexFrance

Personalised recommendations