Isolation and Characterization of Manganese-containing Superoxide Dismutase from Gluconobacter cerinus

Abstract

Among 21 strains of Gluconobacter, Gluconobacter cerinus (IFO 3268) had a thermostable superoxide dismutase activity. The enzyme was purified about 110-fold to homogeneity from a cell-free extract by ammonium sulfate fractionation and DEAE-Toyopearl and Sephadex G-100 chromatography. The enzyme has a molecular weight of 47, 000 and consists of two identical subunits, and contains 1.22 g atoms of Mn per mole of enzyme as the catalytically active metal. The enzyme disappeared from circulation in the guinea pig with a half-life of 45min, but enzyme modified with polyethylene glycol 5, 000 had a half-life of 330 min.