Abstract
The possible involvement of superoxide and hydrogen peroxide in the oxidative gelling of phloem exudate from Cucurbita pepo. was investigated. Neither superoxide dismutase (EC 1.15.1.1) nor catalase (EC 1.11.1.6) inhibited the reaction. Although catalase could not be detected in exudate, both peroxidase (EC. 1.11.1.7) and superoxide dismutase were present in reasonable amounts. Polyacrylamide gel electrophoresis revealed one major and one minor isozyme of superoxide dismutase, both of which were adjudged to contain copper and zinc as their prosthetic metals, on the basis of cyanide inhibition and molecular weight.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- SOD:
-
superoxide dismutase
References
Armstrong, D.A., Buchanan, J.D. (1978) Reactions of O2, H2O2 and other oxidants with sulfhydryl enzymes. Photochem. Photobiol. 28, 743–755
Beauchamp, C., Fridovich, I. (1971) Superoxide dismutase: improved assays and an assay applicable to acrylamide gels. Anal. Biochem. 44, 276–287
Bradford, M.M. (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal. Biochem. 72, 248–254
Dunford, H.B., Stillman, J.S. (1976) On the function and mechanism of action of peroxidases. Coord. Chem. Rev. 19, 187–251
Eschrich, W., Evert, R.F., Heyser, W. (1971) Proteins of the sieve tube exudate of Cucurbita maxima. Planta 100, 208–221
Foster, J.G., Edwards, G.E. (1980) Localization of superoxide dismutase in leaves of C3 and C4 plants. Plant Cell Physiol. 21, 895–906
Hedrick, J.L., Smith, A.J. (1968) Size and charge isomer separation and estimation of molecular weights of proteins by disc gel electrophoresis. Arch. Biochem. Biophys. 126, 155–164
Hill, H.A.O. (1978) The superoxide ion and the toxicity of molecular oxygen. In: New trends in bioinorganic chemistry, pp. 173–208, Frausto da Silva, J.R.R., Williams, R.J.P., eds. Academic Press, London
Kleinig, H., Thönes, J., Dörr, I., Kollmann, R. (1975) Filament formation in vitro of a sieve tube protein from Cucurbita maxima and Cucurbita pepo. Planta 127, 163–170
Marklund, S., Marklund, G. (1974) Involvement of the superoxide anion radical in the autoxidation of pyrogallol and a convenient assay for superoxide dismutase. Eur. J. Biochem. 47, 469–474
Maurer, H.R. (1971) Disc electrophoresis and related techniques of polyacrylamide gel electrophoresis. Walter de Gruyter, Berlin
McCord, J.M., Keele, B.B., Jr., Fridovich, I. (1971) An enzyme-based theory of obligate anaerobiosis: the physiological function of superoxide dismutase. Proc. Natl. Acad. Sci. USA 68, 1024–1027
Milburn, J.A. (1971) An analysis of the response in phloem exudation on application of massage to Ricinus. Planta 100, 143–154
Walker, T.S. (1972) The purification and some properties of a protein causing gelling in phloem sieve tube exudate from Cucurbita pepo. Biochim. Biophys. Acta 257, 433–444
Weber, C., Franke, W.W., Kartenbeck, J. (1974) Structure and biochemistry of phloem-proteins isolated from Cucurbita maxima. Exp. Cell Res. 87, 79–106
Weber, K., Osborn, M. (1969) The reliability of molecular weight determination by dodecyl sulfate-polyacrylamide gel electrophoresis. J. Biol. Chem. 244, 4406–4412
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
McEuen, A.R., Hill, H.A.O. Superoxide, hydrogen peroxide, and the gelling of phloem sap from Cucurbita pepo . Planta 154, 295–297 (1982). https://doi.org/10.1007/BF00393906
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00393906