韭菜过氧化氢酶的分离纯化及其部分酶学特性

为获得韭菜过氧化氢酶纯品并对其性质进行研究，将新鲜韭菜通过匀浆、抽提、硫酸铵分级沉淀、DEAE-Sepharose 离子交换层析、Superdex-200凝胶过滤层析等步骤，获得了电泳纯的韭菜过氧化氢酶(CAT)，纯化倍数为70.36，回收率为18.33%，酶比活力达到22064.57U/mg。其全酶分子质量和亚基分子质量分别为241.76、62.43kD。该酶反应的最适温度为37℃，最适pH值为7.2。该酶在25～40℃以及pH5～9有较好的稳定性，同时在最适条件下测得其Km值为46.93mmol/L。甲醇、乙醇、异丙醇、SDS以及Cu2+、Ag+、Fe2+等金属离子对该酶有较强的抑制作用。

Isolation,Purification and Partial Characterization of Catalase from Chinese Chives

The present study was conducted to obtain high-purity catalase (CAT) from Chinese chives and explore some of its enzymological properties. Electrophoresis-purity CAT was obtained sequentially after homogenization, extraction, fractional ammonium sulfate precipitation, DEAE-Sepharose chromatographic separation and Superdex-200 gel filtration. In the process, a purification factor of 70.36, a recovery of 18.33% and a specific enzyme activity of 22064.57 U/mg were obtained. The enzyme exhibited a molecular weight of 241.76 kD and contained a 62.43 kD subunite. The optimum temperature and pH for this enzyme were 37 ℃ and 7.2, respectively. The CAT enzyme was stable under pH 5－9 and 25－40 ℃ conditions. Its Km was determined to be 46.93 mmol/L under optimum conditions. The enzyme activity could be strongly inhibited by methanol, ethanol, isopropanol, SDS, Cu2+, Ag+, and Fe2+.