الفهرس 
Role of SODs in HumanOnly 14 pages are availabe for public view
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Abstract
This study was carried out in three stages; the first stage concerned with selection of Actinomycetes with high SOD activity, the second stage concerned with optimization of superoxide dismutase productivity from these Actinomycetes and the third stage concerned with purification and characterization of superoxide dismutase. It was found that both Streptomyces sp. E1 and Streptomyces sp. G1 in mesophilic group had the higher intra SOD activity. Streptomyces sp. E1 and Streptomyces sp. G1 were optimized for the production of SOD, the optimum production of SOD by both Streptomyces were found to occur as follows: 1) 6 days incubation period. 2) The best pH value was pH 7.0. 3) 35 ºC was found to be the optimum temperature. 4) 0.05 Molar of the buffering system for Streptomyces sp. E1 and 0.005 for Streptomyces sp. G1,5) Starch was the best carbon source 6) Iron in the form of sulphate salt was found to be the best mineral source. Purification of intracellular SOD by Streptomyces sp. E1 and Streptomyces sp. G1 was carried out by precipitation by 60% ammonium sulfate, calcium phosphate gel, dialysis and gel filteration chromatography by sephadex G50 column. The purification steps led to the increase of specific activity of the SOD enzyme (8387 U / mg and 10398 U / mg) for Streptomyces sp. E1 and Streptomyces sp. G1, respectively and purification factor of 5.3 and 6.7 for Streptomyces sp. E1 and Streptomyces sp. G1, respectively. The activity of the purified SOD from Streptomyces sp. E1 and Streptomyces sp. G1 was optimized: 1) 60 ºc for the optimum temperature and the activation energy was 36.2 and 21.1 KJ for Streptomyces sp. E1 and Streptomyces sp. G1 respectively. 2) 50 min incubation time and the best pH was pH 8.0. The 1st and the 2nd dissociation constant (pKa1 and pKa2) was (5.5 and 8.0) for Streptomyces sp. E1 and (5.5 and 8.2) for Streptomyces sp. G1 indicated the presence of imidazolium and ammonium groups in the enzyme from both microorganisms. SOD purified from Streptomyces sp. E1 and Streptomyces sp. G1 was further charectrized .