A thermostable manganese-containing superoxide dismutase from the thermophilic fungus Thermomyces lanuginosus
A thermostable manganese-containing superoxide dismutase from the thermophilic fungus Thermomyces lanuginosus
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DOI：
10.1007/s00792-004-0413-4
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发表时间：
2005-02-01
期刊：
影响因子：
2.9
通讯作者：
Lu, J
中科院分区：
文献类型：
--
作者：
Li, DC;Gao, J;Lu, J
通过分级硫酸铵沉淀、DEAE-Sepharose 离子交换层析、Phenyl-Sepharose 疏水相互作用层析和 Sephacryl S-100 凝胶过滤，将来自疏棉状嗜热丝孢菌菌株 (P134) 的热稳定性超氧化物歧化酶 (SOD) 纯化至均质。使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳估计该酶的单条带的分子量为22.4 kDa。使用Sephacryl S-100上的凝胶过滤，估计分子量为89.1 kDa，表明该酶由四个相同的亚基组成，每个亚基为22.4 kDa。发现 SOD 被 NaN3 抑制，但不被 KCN 或 H2O2 抑制，这表明 T. lanuginosus 中的 SOD 属于锰超氧化物歧化酶类型。 SOD 在 pH 7.5 时表现出最大活性。该活性的最适温度为55℃。它在 50 和 60℃ 下具有热稳定性，并且在 70℃ 下 60 分钟后仍保留 55% 的活性。 SOD在80℃下的半衰期约为28分钟，在90℃下20分钟后甚至保留了20%的活性。
A thermostable superoxide dismutase (SOD) from a Thermomyces lanuginosus strain (P134) was purified to homogeneity by fractional ammonium sulfate precipitation, ion-exchange chromatography on DEAE-Sepharose, Phenyl-Sepharose hydrophobic interaction chromatography, and gel filtration on Sephacryl S-100. The molecular mass of a single band of the enzyme was estimated to be 22.4 kDa, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Using gel filtration on Sephacryl S-100, the molecular mass was estimated to be 89.1 kDa, indicating that this enzyme was composed of four identical subunits of 22.4 kDa each. The SOD was found to be inhibited by NaN3, but not by KCN or H2O2, suggesting that the SOD in T. lanuginosus was of the manganese superoxide dismutase type. The SOD exhibited maximal activity at pH 7.5. The optimum temperature for the activity was 55degreesC. It was thermostable at 50 and 60degreesC and retained 55% activity after 60 min at 70degreesC. The half-life of the SOD at 80degreesC was approximately 28 min and even retained 20% activity after 20 min at 90degreesC.