高等学校化学学报 ›› 2015, Vol. 36 ›› Issue (4): 698.doi: 10.7503/cjcu20140739

• 有机化学 • 上一篇    下一篇

嗜热古细菌Sulfolobus tokodaii脱卤酶在D-乳酸生产中的应用

解桂秋1, 潘东2, 何文龙2, 高贵2, 高仁钧2()   

  1. 1. 吉林大学药学院, 长春 130021
    2. 吉林大学生命科学学院, 分子酶学工程教育部重点实验室, 长春 130012
  • 收稿日期:2014-08-31 出版日期:2015-04-10 发布日期:2015-03-27
  • 作者简介:联系人简介: 高仁钧, 男, 博士, 教授, 主要从事酶工程研究. E-mail: gaorj@jlu.edu.cn
  • 基金资助:
    国家自然科学基金(批准号: 20772046)和吉林省科技研究和发展计划项目(批准号: 201105011)资助

Application of L-2-Haloacid Dehalogenase from Thermophilic Archaea Sulfolobus Tokodaii in the Production of D-Lactic Acid

XIE Guiqiu1, PAN Dong2, He Wenlong2, GAO Gui2, GAO Renjun2,*()   

  1. 1. College of Pharmacy, Jilin University, Changchun 130021, China
    2. Key Laboratory for Molecular Enzymology and Engineering, Ministry of Education, School of Life Science,Jilin University, Changchun 130012, China
  • Received:2014-08-31 Online:2015-04-10 Published:2015-03-27
  • Contact: GAO Renjun E-mail:gaorj@jlu.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(No.20772046) and the Technologies Research and Development Program of Jilin Province, China(No.201105011)

摘要:

将来源于嗜热古菌Sulfolobus tokodaii的脱卤酶(L-HADST)基因克隆到载体pET28b, 转化大肠杆菌BL21(DE3)进行表达, 在蛋白的N末端带有6个组氨酸融合标签, 纯化后经聚丙烯酰胺凝胶电泳显示融合蛋白的分子量约为25000. 融合蛋白催化2-氯丙酸(2-CPA)的最适反应温度为70 ℃, 最适pH值为9.5. 以外消旋2-CPA为底物生产D-乳酸, 利用HPLC检测反应液中2-CPA及乳酸的变化, 发现L-HADST只催化L-2-CPA脱氯反应. 对酶催化反应条件进行了优化, 结果表明, 在pH值为9.5, 温度为60 ℃的条件下, 当反应体系中缓冲液浓度为3 mol/L, 底物浓度为0.5 mol/L, 酶浓度为3×104 U/L时有较高的底物转化率及乳酸生成量. 依据条件优化结果可知, 影响反应速度的因素有底物浓度、 缓冲液浓度以及酶浓度, 其中底物浓度变化对转换率的影响最明显.

关键词: L-2-卤代酸脱卤酶, 2-氯丙酸, 乳酸

Abstract:

Optical pure lactic acid is a useful chiral intermediate in the synthesis of chiral drugs and materials engineering. For the purpose of environmental-friendly and high stereoselectivity, enzymes were used to resolve racemic mixtures. In this study, we cloned and expressed L-2-haloacid dehalogenase(ST2570) from thermophilic Archaea Sulfolobus tokodaii in Escherichia coli BL21(DE3). The recombinant enzyme was purified to a single band using heat treatment and Ni2+-NTA affinity chromatography. The optimum temperature and pH value of ST2570 were 70 ℃ and 9.5, respectively. The specific activity of purified ST2570 for the hydrolysis of 2-chloropropionic acid was 2963.33 U/mg. For the high enatioselectivity of ST2570, only L-2-chloropropionic acid can be hydrolyzed to produce D-lactic acid during the reaction. With the optimization, the best conditions to produce D-lactic acid were pH of 9.5, temperature of 60 ℃, 3 mol/L of buffer, 0.5 mol/L of 2-chloropropionic acid and 3×104 U/L of ST2570.

Key words: L-2-Haloacid dehalogenase, 2-Chloropropionic acid, Lactic acid

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