Isolation and Characterization of an Iron-Containing Superoxide Dismutase From Water Lily, Nuphar luteum

A cyanide-insensitive superoxide dismutase (EC 1.15.1.1) was purified from leaves of the water lily Nuphar luteum (L.) Sibth. and Smith Subsp. macrophyllum (Small) Beal. The enzyme had a molecular weight of 46,000 and was composed of two equally sized subunits. Metal analysis showed the protein to contain about 1 gram atom of iron per dimer. The iron-containing superoxide dismutase was sensitive to H(2)O(2) as well as to azide. Antibody to the protein did not cross-react with iron superoxide dismutase isolated from the eucaryote Brassica or with algal extracts.