Cyanide Insensitive Iron Superoxide Dismutase in Euglena gracilis Comparison of the Reliabilities of Different Test Systems for Superoxide Dismutases

Abstract

Two proteins (P1 and P2 , with mol weights of 57,500 and 27,500, respectively) were isolated from Euglena gracilis. Both proteins show cyanide-insensitive superoxide dismutase activity in the “classical” superoxide dismutase assay, using xanthine-xanthine oxidase as O2·− generator. If O2·− is generated chemically (autoxidation of reduced anthraquinone), photochemically (illuminated riboflavine) or pulse radiolytically, only protein P1 but not P2 shows SOD activity. Protein P1 contains 1 g atom (determined: 0.82) iron (no Mn or Cu) per mole protein and may thus be defined as iron-superoxide dismutase. Protein P2 , showing the spectral properties of a flavoprotein, exhibits the activities of ferredoxin-NADP-oxidoreductase and “diaphorase”. The cyanide-insensitive SOD-activity of this “diaphorase” in the xanthine oxidase-assay for superoxide dismutase makes this classical and commonly used test unreliable for assaying cyanide insensitive SOD activities. The existence of the “prokaryote-type” of superoxide dismutase (Fe-SOD) in Euglena gracilis is exceptional for an eukaryotic, autotrophically grown organisms.

N2 Fixation by Streptomyces thermoautotrophicus Involves a Molybdenum-Dinitrogenase and a Manganese-Superoxide Oxidoreductase That Couple N2Reduction to the Oxidation of Superoxide Produced from O2by a Molybdenum-CO Dehydrogenase

“…Other components could not be demonstrated. In its overall shape the UV-visible spectrum of St2 was similar to that reported for the "SOD active" protein P1 from Euglena gracilis (28). The spectrum revealed a protein absorption at 276 nm and a broad absorption extending from 310 to 700 nm with a small maximum at 411 nm and a broad shoulder around 474 nm.…”

In situ proteo-metabolomics reveals metabolite secretion by the acid mine drainage bio-indicator, Euglena mutabilis

“…The number following the functional categories represents the number of proteins identified within each of them. The list of the corresponding proteins is presented in Supplementary Tables 2 and 3. superoxide dismutase and hydroperoxide reductase, were also accumulated suggesting existence of adaptation processes to environmental stresses (Lengfelder and Elstner, 1979;Shigeoka et al, 1980;Seaver and Imlay, 2001). Similarly, a membrane-associated, ATP-dependent H þ transporter was found, presumably reflecting an acclimation to the low-pH conditions prevailing in the Carnoulès AMD.…”

Toxic oxygen species and protective systems of the chloroplast

“…In cyanobacteria and green algae the manganese-containing enzyme has been shown to be associated with the chloroplast thylakoids Asada 1979, Lengfelder andElstner 1979). The presence of this form of the isozyme in chloroplasts, specifically in the thylakoids from higher plants, was initially demonstrated by Lumsden and Hall (1974).…”

“…Iron-containing superoxide dismutases were previously thought to be restricted to prokaryotic organisms (Asada et al 1977, 1980, Asada and Kanematsu 1978, with the exception of Euglena gracilis Asada 1979, Lengfelder andElstner 1979). The iron enzyme is found in representatives of at least 5 plant families: Ginkgoaceae, Nymphaceae, Cruciferae, Rutaceae and Solonaceae (Bridges and Salin 1981, Sevilla et al 1984, Kwiatowski et al 1985.…”