title: Manganese superoxide dismutase from a higher plant : Purification of a new Mn-containing enzyme.
abstract: A manganese-containing superoxide dismutase (EC 1.15.1.1) was purified to homogeneity from a higher plant for the first time. The enzyme was isolated fromPisum sativum leaf extracts by thermal fractionation, ammonium sulfate salting out, ion-exchange and gel-filtration column chromatography, and preparative polyacrylamide gel electrophoresis. Pure manganese superoxide dismutase had a specific activity of about 3,000 U mg(-1) and was purified 215-fold, with a yield of 1.2 mg enzyme per kg whole leaf. The manganese superoxide dismutase had a molecular weight of 94,000 and contained one g-atom of Mn per mol of enzyme. No iron and copper were detected. Activity reconstitution experiments with the pure enzyme ruled out the possibility of a manganese loss during the purification procedure. The stability of manganese superoxide dismutase at-20°C, 4°C, 25°C, 50°C, and 60°C was studied, and the enzyme was found more labile at high temperatures than bacterial manganese superoxide dismutases and iron superoxide dismutases from an algal and bacterial origin.
authors.affiliation: Unidad de Bioquímica Vegetal, Estación Experimental del Zaidín, C.S.I.C., Profesor Albareda 1, Granada, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Sevilla
authors.forename: J
authors.initials: J
authors.lastname: López-Gorgé
authors.forename: M
authors.initials: M
authors.lastname: Gómez
authors.forename: L A
authors.initials: LA
authors.lastname: Del Río