Comparison of N-acetyl-L-cysteine and L-cysteine in respect to their transmembrane fluxes

Abstract

The objective of the present study was to compare cysteine and N-acetyl-L-cysteine in respect to their transmembrane fluxes and find out which one is a better available precursor for the cells and thus better supports the intracellular glutathione synthesis. Cysteine can directly participate in glutathione synthesis, whereas N-acetyl-L-cysteine must be first deacetylated before its incorporation to glutathione. In the present study we investigated and compared the efficiencies of cysteine and N-acetyl-L-cysteine influx and efflux through the erythrocyte membrane. Erythrocytes transported both cysteine and N-acetyl-L-cysteine in a concentration-dependent manner. However, our results demonstrated that cysteine crosses the erythrocyte membranes more efficiently as compared to N-acetyl-L-cysteine. Treatment of erythrocytes with 5 mM of cysteine or N-acetyl-L-cysteine for 1 hr raised the intracellular free sulfhydryl group (free-SH) levels to 3.37 ± 0.006 or 2.23 ± 0.08 μ mol/ml erythrocyte, respectively. Cysteine more effectively than N-acetyl-L-cysteine restored the intracellular free-SH level depleted beforehand. In erythrocytes previously depleted of free-SH, 5 mM cysteine raised the free-SH level to 1.45 ± 0.075 μ mol/ml within 1 hr, whereas N-acetyl-L-cysteine at the same concentration raised this level to 0.377 ± 0.034 μmol/ml only. The results of our study also revealed that both cysteine and N-acetyl-L-cysteine influx and efflux processes are temperature dependent indicating that their transport requires biological activity. Our results demonstrate that cysteine is a better thiol precursor for the erythrocytes. Availability of cysteine for the cells is higher than that of N-acetyl-L-cysteine.

This is a preview of subscription content, access via your institution.

References

  1. 1.

    Murray, R.K., Granner, D.K., Mayes, P.A., and Rodwell, V.W., Biosynthesis of Nutritionally Nonessential Amino Acids. Harper’s Biochemistry, 22nd Ed., USA: Appleton and Lange, 1991, pp. 267–269.

    Google Scholar 

  2. 2.

    McBean, G.J. and Flynn, J., Molecular Mechanism of Cystine Transport, Biochem. Soc. Transact., 2001, vol. 29, no. 6, pp. 717–722.

    Article  CAS  Google Scholar 

  3. 3.

    Griffith, O.W., Biological and Pharmacological Regulation of Mammalian Glutathione Synthesis, Free Rad. Biol. Med., 1999, vol. 27, pp. 922–935.

    PubMed  Article  CAS  Google Scholar 

  4. 4.

    Sies, H., Glutathione and Its Role in Cellular Functions, Free Rad. Biol. Med., 1999, vol. 27, pp. 916–921.

    PubMed  Article  CAS  Google Scholar 

  5. 5.

    Eckert, K.G. and Eyer, P., Formation and Transport of Xenobiotic Glutathione-S-Conjugates in Red Cells, Biochem. Pharmacol., 1986, vol. 35, no. 2, pp. 325–329.

    PubMed  Article  CAS  Google Scholar 

  6. 6.

    Flora, S.D., Izzotti, A., D’Agostini, D., and Balansky, R.M., Mechanism of N-Acetylcysteine in the Prevention of DNA Damage and Cancer, with Special Reference to Smoking-Related End-Points, Carcinogenesis, 2001, vol. 22, no. 7, pp. 999–1013.

    PubMed  Article  Google Scholar 

  7. 7.

    De Vries, N. and De Flora, S., N-acetyl-L-cysteine, J. Cellular Biochem. (Suppl. 17F), 1993, pp. 270–277.

  8. 8.

    Kelly, G.S., Clinical Applications of N-Acetylcysteine, Alt. Med. Rev., 1998, vol. 3, no. 2, pp. 114–127.

    CAS  Google Scholar 

  9. 9.

    De Flora, S., Bennicelli, C., Camoirano, A., Serra, D., Romano, M., Rossi, G.A., Morelli, A., and De Flora, A., In vivo Effects of N-Acetylcysteine on Glutathione Metabolism and on the Biotransformation of Carcinogenic and/or Mutagenic Compounds, Carcinogenesis, 1985, vol. 6, pp. 1735–1745.

    PubMed  Article  Google Scholar 

  10. 10.

    Nakata, K., Kawase, M., Ogino, S., Kinoshita, C., Murata, H., Sakaue, T., Ogata, K., and Ohmori, S., Effects of Age on Levels of Cysteine, Glutathione and Related Enzyme Activities in Livers of Mice and Rats and an Attempt to Replenish Hepatic Glutathione Level of Mouse with Cysteine Derivatives, Mech. Ageing Dev., 1996, vol. 90, pp. 195–207.

    PubMed  Article  CAS  Google Scholar 

  11. 11.

    Hoffer, E., Baum, Y., Tabak, A., and Taitelman, U., N-Acetylcysteine Increases the Glutathione Content and Protects Rat Alveolar Type II Cells Against Paraquat-Induced Cytotoxicity, Toxicol. Lett., 1996, vol. 84, pp. 7–12.

    PubMed  Article  CAS  Google Scholar 

  12. 12.

    Corcoran, G.B. and Wong, B.K., Role of Glutathione in Prevention of Acetaminophen-Induced Hepatotoxicity by N-Acetyl-L-Cysteine in vivo: Studies with N-Acetyl-D-Cysteine in Mice, J. Pharm. Exp. Ther., 1986, vol. 238, pp. 54–61.

    CAS  Google Scholar 

  13. 13.

    Pratt, S. and Ioannides, C., Mechanism of the Protective Action of N-Acetylcysteine and Methionine Against Paracetamol Toxicity in the Hamster, Arch. Toxicol., 1985, vol. 57, pp. 173–177.

    PubMed  Article  CAS  Google Scholar 

  14. 14.

    Awasthi, Y.C., Misra, G., Rassin, D.K., and Srivastava, S.K., Detoxification of Xenobiotics by Glutathione S-Transferase in Erythrocytes: the Transport of the Conjugate of Glutathione and 1-Chloro-2,4-Dinitrobenzene, Brit. J. Haematol., 1983, vol. 55, pp. 419–425.

    Article  CAS  Google Scholar 

  15. 15.

    Sedlak, J. and Lindsay, R.H., Determination of Sulfhydryl Groups in Biological Samples, Anal. Biochem., 1963, vol. 25, pp. 192–205.

    Article  Google Scholar 

  16. 16.

    Palacin, M., Estevez, R., Bertran, J., and Zorzano, A., Molecular Biology of Mammalian Plasma Membrane Amino Acid Transporters, Physiol. Rev., 1998, vol. 78, pp. 969–1054.

    PubMed  CAS  Google Scholar 

  17. 17.

    Rosenberg, R., Na-Independent and Na-Dependent Transport of Neutral Amino Acids in the Human Red Blood Cells, Acta. Physiol. Scand., 1982, vol. 116, pp. 321–330.

    PubMed  Article  CAS  Google Scholar 

  18. 18.

    Bonanomi, L. and Gazzaniga, A., Toxicological, Pharmacokinetic and Metabolic Studies on Acetylcysteine, Eur. J. Respir. Dis., 1980, vols. 45–51, p. 61.

    Google Scholar 

  19. 19.

    De Caro, L., Ghizzi, A., and Costa, R., Pharmacokinetics and Bioavailability of Oral Acetylcysteine in Healthy Volunteers, Arzneim. Forsch., 1989, vol. 39, pp. 382–385.

    Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to D. Yildiz.

Additional information

The article is published in the original.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Yildiz, D., Arik, M., Cakir, Y. et al. Comparison of N-acetyl-L-cysteine and L-cysteine in respect to their transmembrane fluxes. Biochem. Moscow Suppl. Ser. A 3, 157–162 (2009). https://doi.org/10.1134/S1990747809020081

Download citation

Key words

  • cysteine
  • N-acetyl-L-cysteine (NAC)
  • erythrocytes
  • transmembrane transport