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Plant Physiology 70:1321-1326 (1982) © 1982 American Society of Plant Biologists Characterization of a Manganese Superoxide Dismutase from the Higher Plant Pisum sativum1Unidad de Bioquímica Vegetal, Estación Experimental del Zaidín, C. S. I. C., Profesor Albareda 1, Granada, Spain
A manganese-containing superoxide dismutase (EC 1.15.1.1) was fully characterized from leaves of the higher plant Pisum sativum L., var. Lincoln. The amino acid composition determined for the enzyme was compared with that of a wide spectrum of superoxide dismutases and found to have a highest degree of homology with the mitochondrial manganese superoxide dismutases from rat liver and yeast. The enzyme showed an apparent pH optimum of 8.6 and at 25°C had a maximum stability at alkaline pH values. By kinetic competition experiments, the rate constant for the disproportionation of superoxide radicals by pea leaf manganese superoxide dismutase was found to be 1.61 x 109 molar1·second1 at pH 7.8 and 25°C. The enzyme was not sensitive to NaCN or to H2O2, but was inhibited by N3. The sulfhydryl reagent p-hydroxymercuribenzoate at 1 mM concentration produced a nearly complete inhibition of the manganese superoxide dismutase activity. The metal chelators o-phenanthroline, EDTA, and diethyldithiocarbamate all inhibited activity slightly in decreasing order of intensity. A comparative study between this higher plant manganese superoxide dismutase and other dismutases from different origins is presented.
1 This work was supported by a research grant from the Comisión Asesora de Investigación Científica Técnica (Spain). This article has been cited by other articles:
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