The nature and localization of superoxide dismutase in fronds of Lemna gibba L. and the effect of copper and zinc deficiency on its activity |
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Authors: | D. Vaughan P. C. DeKock B. G. Ord |
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Affiliation: | Dept. of Soil Organic Chemistry, The Macaulay Inst. for Soil Res., Craigiebuckler, Aberdeen AB9 2QJ, U.K. |
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Abstract: | Superoxide dismutase (SOD) is present in the fronds of Lemna gibba L. Differential centrifugation showed that ca. 90% of the enzyme is present in the 140,000 g soluble cell fraction. Lemna SOD is sensitive to cyanide and is probably a Cu-Zn metallo-protein. Gel filtration showed the SOD to have a mass of 31,000 daltons. In Zn-defizient culture media, the activity of Lemna SOD was less than in fronds grown in complete nutrient media whereas in Cu-deficient media little change was found in the enzyme activity. The SOD activity in Zn-deficient plants could be partly restored to the level of Zn-sufficient fronds by adding Zn2+ to the enzyme assay solution. |
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Keywords: | Cell fractionation cyanide-sensitivity duckweed molecular weight |
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