食品科学 ›› 2007, Vol. 28 ›› Issue (12): 258-262.

• 生物工程 • 上一篇    下一篇

来自基因工程菌E.coli BL21/pET-DsbA-MalQ的麦芽糖转糖基酶的分离纯化及酶学性质研究

 王水兴, 龚珩, 郭勇, 夏慧玲, 吴凌伟   

  1. 南昌大学中德联合研究院; 九江学院医学院; 华南理工大学生物科学与工程学院; 南昌大学中德联合研究院 江西南昌330047; 江西九江332005; 广东广州510641; 江西南昌330047;
  • 出版日期:2007-12-15 发布日期:2011-11-22

Purification and Characterization of Amylomaltase from Genetic Engineer Strain E.coli BL21/pET-DsbA-MalQ

 WANG  Shui-Xing, GONG  Hang, GUO  Yong, XIA  Hui-Ling, WU  Ling-Wei   

  1. 1.Jiangxi-OAI Research Institute, Nanchang University, Nanchang 330047,China; 2.Medical College, Jiujiang University, Jiujiang 332005, China; 3.College of Bioscience and Biotechnology, South China University of Technology, Guangzhou 510641, China
  • Online:2007-12-15 Published:2011-11-22

摘要: 通过6-His的分离标签,联合采取硫酸铵沉淀,生物半透膜透析和亲和层析等方法,纯化了目标酶。通过使用凝血酶切割DsbA-MalQ融合蛋白,证明酶切后酶蛋白仍具有麦芽糖转糖基酶活性。该酶的最适温度为37℃,最适pH值为6.5。当处理温度小于40℃时,酶的活力基本保持在最高活性的80%以上,相对稳定;在酶的pH耐受方面,在pH5.5~8.0范围内较稳定。金属离子和EDTA对酶活性的影响实验表明,EDTA对酶活的影响不大,但Zn2+、Cu2+、Hg2+、Ag+对酶蛋白有较强的抑制作用,而Ca2+、Mg2+、Mn2+等对表达的酶有一定的激活作用。在37℃,pH6.5时以麦芽三糖为底物测得酶促反应的Km值为0.378mmol/L,Vmax值为1.979mmol/(L·min)。

关键词: 麦芽糖转糖基酶, 酶学性质, 纯化, 亲和层析

Abstract: The fusion protein was purified by Ni-NTA His-Bind affinity chromatography and cut with thrombin. The purified protein had 4-α-glucanotransferase activities. Its optimum pH and optimum temperature were 37 ℃ and pH 6.5, respectively. When the enzyme was treated at different temperature or pH, the enzyme activity would show different. When the treated temperature was over 40 ℃ or the treated pH below 4.5 or over 9.0, the enzyme activity would decrease quickly. Influences of ions and EDTA on enzyme activity were studied. The results showed that ions Zn2+, Cu2+, Hg2+, Ag+ inhibited enzyme activity, ion Ca2+, Mg2+, Mn2+ increased the enzyme activity, while EDTA showed no such effects on the enzymes. The Km and Vmax were 0.378 mmol/L and 1.979 mmol/(L·min), respectively.

Key words: amylomaltase, characterization of enzyme, purification, affinity chromatography