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为了了解鼠伤寒沙门菌超氧化物歧化酶SodA的生物学功能,本试验经过克隆后表达、纯化而获得了重组SodA蛋白,克隆的SodA基因的序列长度为621 bp,重组SodA蛋白的分子质量为23.7 ku。通过邻苯三酚自氧化法测定了SodA酶比活性。测定结果显示,SodA的最适温度为40℃,最适pH为7.0;Mn~(2+)、Zn~(2+)、Cu~(2+)可以提升SodA酶活性,SDS、氯仿-乙醇、Fe~(3+)能抑制SodA催化效率,H_2O_2、Mg~(2+)、Ca~(2+)、Ba~(2+)、Na~+、K~+对蛋白活性无影响;SodA催化邻苯三酚的νmax为2.03 U/min,κm为0.801 mmol/L。过氧化氢酶CAT对SodA活性的影响研究结果显示,在CAT存在条件下,SodA的耐酸碱、抗乙醇能力得到增强,温度稳定性无明显变化,说明CAT可以增强SodA活性。上述研究结果为深入研究鼠伤寒沙门菌超氧化物歧化酶SodA的功能奠定了基础。
In order to understand the biological function of S. typhimurium superoxide dismutase SodA, recombinant SodA protein was obtained after cloning, purified and purified. The sequence length of the cloned SodA gene was 621 bp. The molecular mass of the recombinant SodA protein was 23.7 ku. The specific activity of SodA was determined by pyrogallol autoxidation. The results showed that the optimal temperature for SodA was 40 ℃, and the optimum pH was 7.0. The activity of SodA was enhanced by Mn ~ (2 +), Zn ~ (2 +) and Cu ~ (2+) , Fe ~ (3+) can inhibit the catalytic efficiency of SodA, H 2 O 2, Mg 2+, Ca 2+, Ba 2+, Na +, K + The νmax of the catalyzed pyrogallol was 2.03 U / min and κm was 0.801 mmol / L. The results of catalase CAT on the activity of SodA showed that in the presence of CAT, the ability of acid-base and ethanol-resistant of SodA was enhanced and the temperature stability did not change significantly, indicating that CAT can enhance the activity of SodA. These results provide a basis for further study on the function of SodA of S. typhimurium.