食品科学 ›› 2011, Vol. 32 ›› Issue (15): 148-152.doi: 10.7506/spkx1002-6630-201115034

• 生物工程 • 上一篇    下一篇

定点突变提高Thermococcus siculi HJ21高温酸性α-淀粉酶催化活性

姚 婷,李华钟,房耀维,陆兆新王淑军,*,焦豫良,刘 姝   

  1. 1.江南大学 工业生物技术教育部重点实验室 2.淮海工学院海洋学院 3.南京农业大学食品科技学院
  • 出版日期:2011-08-15 发布日期:2011-07-26
  • 基金资助:
    国家自然科学基金项目(40746030);江苏省科技厅农业科技支撑计划项目(BE2008340); 江苏省高校自然科学基础研究项目(08KJB550001)

Catalytic Activity Improvement of Acid-stable Alpha-Amylase from Hyperthermophilic Thermococcus siculi HJ21 by Site-directed Mutagenesis

YAO Ting1,2,LI Hua-zhong1,FANG Yao-wei2,LU Zhao-xin3,WANG Shu-jun2,*,JIAO Yu-liang2,LIU Shu2   

  1. (1. The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China ; 2. School of Marine Science and Technology, Huaihai Institute of Technology, Lianyungang 222005, China; 3. College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China)
  • Online:2011-08-15 Published:2011-07-26

摘要: 通过分析超嗜热古菌Thermococcus siculi HJ21高温酸性α-淀粉酶基因,对6个可能提高酶催化活性的氨基酸残基进行定点突变,获得比未突变酶催化活性较高的突变子Y184H、Y121S、A109V、K98R、V125L。将以上5个突变位点集中在一个突变子上得到突变酶TSAM-23,该突变酶与未突变酶相比,酶的催化效率有较大提高,酶的活力和90℃条件下的热稳定性分别提高了3.75倍和2.4%,最适反应pH值为5.0,比未突变酶降低0.5,较之突变前有更好的工业应用价值。

关键词: α-淀粉酶, 催化活性, 定点突变

Abstract: Based on the analysis of hyperthermophilic acid-stable α-amylase gene from Thermococcus siculi HJ21 (TSA), site-directed mutagenesis of six amino acid residues could improve the catalytic activity of α-amylase. Five mutants with higher catalytic activity were identified as K98R, A109V, Y121S, V125L and Y184H, respectively. Subsequent recombination of the mutants produced a mutant enzyme named as TSAM-23. Compared with TSA, the catalytic activity of TSAM-23 was enhanced significantly. The catalytic activity and thermal stability of TSAM-23 at 90 ℃were increased by 3.75 times and 2.4%, respectively. TSAM-23 had an optimal pH of 5.0, which revealed a decrease of 0.5 when compared with TSA.

Key words: α-amylase, catalytic activity, site-directed mutagenesis

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