A novel superoxide dismutase (referred hereafter to as HsSOD) from the psychrophilic bacterium Halomonas sp. ANT108 was purified and characterized. Escherichia coli (E. coli) was selected as the expression host. After recombinant HsSOD (rHsSOD) was purified, the specific activity was determined to be 213.47 U/mg with a purification ratio of approximately 3.61-fold. SDS-PAGE results demonstrated that rHsSOD has the molecular weight of 31.3 kDa, and type identification revealed that it belongs to Cu/Zn SOD. The optimum activity of rHsSOD was at 35 °C and 28% of its maximum activity remained at 0 °C. Further enzymatic assays indicated that rHsSOD exhibited thermal instability with a half-life of 20 min at 60 °C. Moreover, Cu2+ and Zn2+ significantly promoted rHsSOD activity. The values of Km and Vmax were 0.33 mM and 476.19 U/mg, respectively. Interestingly, rHsSOD could avoid DNA strand breakage formed by metal-catalyzed oxidation, demonstrating its antioxidant capacity. To summarize, the results suggested that rHsSOD has relatively high catalytic efficiency and oxidation resistance at low temperatures.

中文翻译：

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纯化，生化特性和DNA保护免受来自嗜冷细菌Haloomonas sp。的新型重组超氧化物歧化酶的氧化损伤。ANT108。

嗜冷细菌Haloomonas sp。的一种新型超氧化物歧化酶（以下称为HsSOD）。ANT108被纯化并表征。选择大肠杆菌（E.coli）作为表达宿主。纯化重组HsSOD（rHsSOD）后，比活性经测定为213.47 U / mg，纯化比率约为3.61倍。SDS-PAGE结果表明，rHsSOD的分子量为31.3 kDa，类型鉴定表明它属于Cu / Zn SOD。rHsSOD的最佳活性为35°C，最大活性的28％保持在0°C。进一步的酶促测定表明，rHsSOD表现出热不稳定性，在60°C下的半衰期为20分钟。此外，Cu2 +和Zn2 +显着提高了rHsSOD活性。Km和Vmax分别为0.33 mM和476.19 U / mg。有趣的是，rHsSOD可以避免金属催化氧化形成的DNA链断裂，证明其抗氧化能力。总而言之，结果表明rHsSOD在低温下具有相对较高的催化效率和抗氧化性。