食品科学 ›› 2012, Vol. 33 ›› Issue (23): 160-165.

• 生物工程 • 上一篇    下一篇

重组脂肪氧合酶基因工程菌破碎条件优化及其酶活力测定方法研究

郭芳芳,应 琦,张 充,陆兆新,别小妹,赵海珍,吕凤霞*   

  1. 南京农业大学食品科技学院
  • 收稿日期:2012-09-16 修回日期:2012-11-26 出版日期:2012-12-15 发布日期:2012-12-12
  • 通讯作者: 吕凤霞 E-mail:lufengxia@njau.edu.cn
  • 基金资助:

    国家自然科学基金资助项目;江苏省科技支撑计划项目;苏州市科技支撑计划

Optimization of Conditions for Disruption of Recombinant E. coli Cells and Determination of Lipoxygenase Activity

lu fengxia   

  • Received:2012-09-16 Revised:2012-11-26 Online:2012-12-15 Published:2012-12-12
  • Contact: lu fengxia E-mail:lufengxia@njau.edu.cn

摘要: 建立适用于从重组E.coli中提取重组脂肪氧合酶非机械法的破碎条件。采用化学渗透法、冻融法和酶解法破碎重组E.coli细胞,并采用单因素试验和L25(56)正交试验对细胞破碎条件进行优化。结果表明:溶菌酶添加量为1.5mg/mL、溶菌酶处理时间40min、乙二胺四乙酸二钠(EDTA-2Na)添加量为2.0mmol/L、吐温-60添加量为2%、冻融温度(-70℃冷冻37℃融解)、冻融次数3次,效果最佳,获得粗酶液的脂肪氧合酶(LOX)酶活力为6840U/mL,比优化前(4750U/mL)提高了0.44倍;并在此条件下,比较分光光度法、碘化钾-淀粉法和二甲苯酚橙法测定LOX酶活力,其中碘化钾-淀粉法简单、灵敏、快速,且测定体系具备肉眼可辨的特征颜色,可用于LOX酶活性高通量筛选。

关键词: 脂肪氧合酶, 化学渗透法, 冻融法, 酶解法, 酶活力测定法

Abstract: Recombinant E. coli cells were disrupted by combined non-mechanical methods, such as chemical permeation, repeated freeze-thaw and enzymatic lysis for the extraction of recombinant lipoxygenase (LOX). Based on one-factor-at-a-time experiments, an L25(56) orthogonal array design was employed to optimize five process parameters. The best results for bacterial cell disruption were achieved through enzymatic lysis with 1.5 mg/mL of lysozyme for 40 min in the presence of 2.0 mmoL/L EDTA-2Na and 2% Tween-60 followed by 3 repeated freeze-thaw cycles, yielding an LOX activity of 6840 U/mL in crude enzyme solution, which was 1.44-fold higher than before the optimization. Compared with spectrophotometry and xylenol orange method, potassium iodide-starch method was more simple, sensitive and rapid and the reaction system showed characteristic color visible to the naked eye. Thus, this method is suitable for high throughput screening of LOX activity.

Key words: lipoxygenase, chemical permeation, freeze-thaw, enzymatic lysis, enzyme activity assay