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Purification of camel liver catalase by zinc chelate affinity chromatography and pH gradient elution: An enzyme with interesting properties
Journal of Chromatography B ( IF 2.8 ) Pub Date : 2017-10-27 , DOI: 10.1016/j.jchromb.2017.10.052
Abdelbasset Chafik , Abdelkhalid Essamadi , Safinur Yildirim Çelik , Ahmet Mavi

Climate change and increasing temperatures are global concerns. Camel (Camelus dromedarius) lives most of its life under high environmental stress in the desert and represent ideal model for studying desert adaptation among mammals. Catalase plays a key role in protecting cells against oxidative stress. For the first time, catalase from camel liver was purified to homogeneity by zinc chelate affinity chromatography using pH gradient elution, a better separation was obtained. A purification fold of 201.81 with 1.17% yield and a high specific activity of 1132539.37 U/mg were obtained. The native enzyme had a molecular weight of 268 kDa and was composed of four subunits of equal size (65 kDa). The enzyme showed optimal activity at a temperature of 45 °C and pH 7.2. Thiol reagents, β-Mercaptoethanol and D,L-Dithiothreitol, inhibited the enzyme activity. The enzyme was inhibited by Al3+, Cd2+ and Mg2+, whereas Ca2+, Co2+ and Ni2+ stimulated the catalase activity. Reduced glutathione has no effect on catalase activity. The Km and Vmax of the enzyme for hydrogen peroxide were 37.31 mM and 6185157 U/mg, respectively. Sodium azide inhibited the enzyme noncompetitively with Ki value of 14.43 μM, the IC50 was found to be 16.71 μM. The properties of camel catalase were different comparing to those of mammalian species. Relatively higher molecular weight, higher optimum temperature, protection of reduced glutathione from hydrogen peroxide oxidation and higher affinity for hydrogen peroxide and sodium azide, these could be explained by the fact that camel is able to live in the intense environmental stress in the desert.



中文翻译:

螯合锌亲和层析和pH梯度洗脱纯化骆驼肝过氧化氢酶:一种具有有趣特性的酶

气候变化和温度升高是全球关注的问题。骆驼(Camelus dromedarius)的大部分生命都在沙漠中处于高环境压力下,代表了研究哺乳动物之间沙漠适应的理想模型。过氧化氢酶在保护细胞免受氧化应激中起关键作用。首次使用pH梯度洗脱通过锌螯合亲和层析将骆驼肝中的过氧化氢酶纯化至均一,获得了更好的分离效果。获得201.81的纯化倍数,产率为1.17%,比活性高,为1132539.37 U / mg。天然酶的分子量为268 kDa,由相等大小(65 kDa)的四个亚基组成。该酶在45°C和pH 7.2的条件下显示出最佳活性。硫醇试剂β-巯基乙醇和D,L-二硫苏糖醇可抑制酶的活性。该酶被Al 3+,Cd抑制2+和Mg 2+,而Ca 2 +,Co 2+和Ni 2+刺激过氧化氢酶活性。还原型谷胱甘肽对过氧化氢酶活性没有影响。过氧化氢酶的K m和V max分别为37.31 mM和6185157 U / mg。叠氮化钠非竞争性抑制酶,K i值为14.43μM,IC 50发现为16.71μM。骆驼过氧化氢酶的性质与哺乳动物相比有所不同。相对较高的分子量,较高的最佳温度,保护还原型谷胱甘肽免受过氧化氢氧化以及对过氧化氢和叠氮化钠具有更高的亲和力,这可以通过以下事实来解释:骆驼能够生活在沙漠中强烈的环境压力下。

更新日期:2017-10-27
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