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首页> 外文期刊>Journal of enzyme inhibition >Purification and characterization of catalase from chard (Beta vulgaris var. cicla).
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Purification and characterization of catalase from chard (Beta vulgaris var. cicla).

机译：唐莴苣（Beta vulgaris var。cicla）中过氧化氢酶的纯化和鉴定。

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Catalase is a major primary antioxidant defence component that primarily catalyses the decomposition of H(2) O(2) to H(2) O. Here we report the purification and characterization of catalase from chard (Beta vulgaris var. cicla). Following a procedure that involved chloroform treatment, ammonium sulfate precipitation and three chromatographic steps (CM-cellulose, Sephadex G-25, and Sephadex G-200), catalase was purified about 250-fold to a final specific activity of 56947 U/mg of protein. The molecular weight of the purified catalase and its subunit were determined to be 235 000 and 58 500 daltons, indicating that the chard catalase is a tetramer. The absorption spectra showed a soret peak at 406 nm, and there was slightly reduction by dithionite. The ratio of absorption at 406 and 275 nanometers was 1.5, the value being similar to that obtained for catalase from other plant sources. In the catalytic reaction, the apparent Km value for chard catalase was 50 mM. The purified protein has a broad pH optimum for catalase activity between 6.0 and 8.0. The enzyme had an optimum reaction temperature at 30 degrees C. Heme catalase inhibitors, such as azide and cyanide, inhibited the enzyme activity markedly and the enzyme was also inactivated by ?-mercaptoethanol, dithiothreitol and iodoacetamide.
机译：过氧化氢酶是主要的主要抗氧化剂防御成分，主要催化H（2）O（2）分解为H（2）O。在这里，我们报道了从唐莴苣（Beta vulgaris var.cicla）纯化和表征过氧化氢酶。按照涉及氯仿处理，硫酸铵沉淀和三个色谱步骤（CM-纤维素，Sephadex G-25和Sephadex G-200）的程序进行，过氧化氢酶的纯度约为250倍，最终比活度为56947 U / mg。蛋白。纯化的过氧化氢酶及其亚基的分子量测定为235000和58500道尔顿，表明甜菜过氧化氢酶是四聚体。吸收光谱在406nm处有一个soret峰，连二亚硫酸盐略有减少。 406和275纳米处的吸收比为1.5，该值与从其他植物来源获得的过氧化氢酶相似。在催化反应中，甜菜过氧化氢酶的表观Km值为50mM。纯化的蛋白质对过氧化氢酶活性的最适pH范围在6.0至8.0之间。该酶的最佳反应温度为30℃。叠氮化物和氰化物等血红素过氧化氢酶抑制剂显着抑制了酶的活性，并且该酶也被β-巯基乙醇，二硫苏糖醇和碘乙酰胺灭活。

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