Superoxide dismutase molecular properties

Forman and Fridovich (1973) using an indirect assay whereby O2 was generated either by the action of xanthine oxidase on xanthine or by the mechanical infusion of potassium superoxide in tetrahydrofuran. The generated OJ was allowed to react with ferricytochrome c or with tetra-nitromethane and the product formation was monitored spectroscopically. Details of the two assays are given in Section 11.3. Addition of superoxide dismutase inhibits the formation of products. A rate constant of 2 X 10 M sec was determined for all three enzymes. This value agreed with the rate constant determined by pulse radiolysis for the copper/zinc enzyme (Klug-Roth et al., 1973 Fielden et al., 1974). The mechanism of action of the superoxide dismutases has been investigated by the technique of pulse radiolysis which is described in Section II.2. The bovine erythrocyte copper/zinc enzyme is the most studied form as far as the molecular and catalytic properties are concerned (Rotilio and Fielden,... 

This phenomenon is not observed using SOD which was previously treated with organic solvents or lyophilized enzyme from either source stored for three months. It was suggested, that the molecular architecture of the active center of aqueously isolated enzyme differs from that of the other species The molecular properties of the SOD s summarized in the next chapter are essentially all derived from data collected from the enzyme which was isolated employing the diloroform/ethanol method. Data from Cu Zn superoxide dismutases obtained by other isolation methods are awaited with great interest. 

Vujaskovic Z, Batinic-Haberle I, Rabbani ZN et al. (2002a) A small molecular weight catalytic metalloporphyrin antioxidant with superoxide dismutase (SOD) mimetic properties protects lungs from radiation-induced injury. Free Radical Biol Med 33 857-863... 

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