Abstract
Redox activities associated with plasma membranes of nonphagocytic animal and plant cells have been reported by several authors. However, the natural substrates, structure and biological role of these putative enzyme systems are not known. Data indicating extracellular reduction of a nitroxide free radical Cat1 (1-oxy-4-trimethylamine-2,2,6,6,tetramethyl-piperidine) by hepatocytes were thought to be artefactual. We report evidence in support of a notion that Cat1 as well as a tetrazolium salt, CTC (5-cyano-2,3-ditolyl tetrazolium chloride), are reduced extracellularly, probably at the cell surface, by human HepG2 hepatoma cells. These data provide evidence confirming the existence of a yet unidentified reducing activity associated with outer surface of plasma membranes of transformed human hepatocytes.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
Brightman, A. O., Wang, J., Kin-man Miu, R., Sun, I. L., Barr, R., and Morre, D. J. (1992) Biochim. Biophys. Acta 1105:109–117.
Cherry, J. M., MacKellar, W., Morre, D. J., Crane, F. L., Jacobsen, L. B., and Schirrmacher, V. (1981) Biochim. Biophys. Acta 634:11–18.
Clark, M. G., Patrick, E. J., Patten, G. S., Crane, F. L., Low, H., and Grebing, C. (1981) Biochem. J. 200:565–572.
Crane, F. L., Sun, I. L., Clark, M. G., Grebing, C., and Low, H. (1985) Biochim. Biophys. Acta 811:233–264.
Shallreuter, K. U. and Wood, J. W. (1986) Biochem. Biophys. Res. Commun. 136:630–637.
Sun, I. L., Navas, P., Crane, F. L., Morre, D. J., and Low, H. (1987) J. Biol. Chem. 262:15915–15921.
Parente, J. E., Wong, K., and Davis, P. (1986) Inflammation 10:303–310.
Tamura, M., Tamura, T., Burnham, D. N., Uhlinger, D. J., and Lambeth, J. D. (1989) Arch. Biochem. Biophys. 275:23–32.
Mersel, M., Malviya, A. N., Hindelang, C., and Mandel, P. (1984) Biochim. Biophys. Acta 778:144–154.
Sun, I. L., Crane, F. L., Chou, J. Y., Low, H., and Grebing, C. (1983) Biochem. Biophys. Res. Commun. 116:210–216.
Stellmach, J. (1984) Histochemistry 80:137–143.
Stellmach, J. and Severin, E. (1987) Histochem. J. 19:21–26.
Chen, K., Morse, P. D. I., and Swartz, H. M. (1988) Biochim. Biophys. Acta 943:477–484.
Kotcherginsky, N. and Swartz, H. M. (1995) in: Nitroxide Spin Labels, CRC Press, Boca Raton, New York, London, Tokyo, pp. 25–65 and 126–134.
Iannone, A., Tomassi, A., Vanini, V., and Swartz, H. M. (1990) Biochim. Biophys. Acta 1034:285–295.
Eriksson, U. G., Tozer, T. N., Sosnowsky, G., Lukszo, J., and Brash, R. C. (1986) J. Pharm. Sci. 75:334–337.
Iannone, A., Hu, H., Vannini, V., and Swartz, H. M. (1989) Biochim. Biophys. Acta 991:90–96.
Swartz, H. M., Sentjurc, M., and Morse, P. D. (1986) Biochim. Biophys. Acta 888:82–90.
Todd, A. P., Melhorn, J., and Macey, R. I. (1989) J. Membr. Biol. 109:53–64.
Keana, J. F., Sovitj, P., and Rosen, G. M. (1987) Magn. Res. Med. 5:525–536.
Scharllreuter, K. and Wood, J. M. (1988) Biochim. Biophys. Acta 967:103–109.
Nettleton, D. O., Morse, P. D. I., and Swartz, H. M. (1988) Arch. Biochem. Biophys. 271:414–423.
Blumrich, M. and Petzinger, M. (1990) Biochim. Biophys. Acta 1029:1–12.
Doussiere, J. and Vignais, P. V. (1992) Eur. J. Biochem. 208:61–71.
Yosioka, K. (1984) Biochim. Biophys. Acta 778:201–209.
Yosioka, K. and Nishimura, H. (1988) Experientia 44:889–892.
Bakoy, O. E. and Thorstensen, K. (1994) Eur. J. Biochem. 222:105–112.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bernas, T., Dobrucki, J. Extracellular Reduction of Cat1 Free Radical by Transformed Human Hepatocytes. Biosci Rep 18, 341–350 (1998). https://doi.org/10.1023/A:1020213400556
Issue Date:
DOI: https://doi.org/10.1023/A:1020213400556