食品科学 ›› 2013, Vol. 34 ›› Issue (21): 158-162.doi: 10.7506/spkx1002-6630-201321033

• 生物工程 • 上一篇    下一篇

两种化学修饰剂对小麦酯酶活性及稳定性的影响

陈 铭1,陆利霞1,2,*,熊晓辉1,2,游京晶1,2   

  1. 1.南京工业大学食品与轻工学院,江苏 南京 210009;2.江苏省食品安全快速检测公共技术服务中心,江苏 南京 210009
  • 收稿日期:2013-04-25 修回日期:2013-10-11 出版日期:2013-11-15 发布日期:2013-10-28
  • 通讯作者: 陆利霞 E-mail:xiaoming_318@163.com
  • 基金资助:

    “十二五”农村领域国家科技计划项目(2013BAD19B09);江苏省科技基础设施建设计划项目(BM2012026)

Two Chemical Modifiers Affect Wheat Esterase Activity and Stability

CHEN Ming1,LU Li-xia1,2,*,XIONG Xiao-hui1,2,YOU Jing-jing1,2   

  1. 1. College of Food Science and Light Industry, Nanjing University of Technology, Nanjing 210009, China;
    2. Jiangsu Public Technical Service Center for Rapid Detection of Food Safety, Nanjing 210009, China
  • Received:2013-04-25 Revised:2013-10-11 Online:2013-11-15 Published:2013-10-28
  • Contact: LU Li-xia E-mail:xiaoming_318@163.com

摘要:

目的:用右旋糖酐和单甲氧基聚乙二醇(mPEG)化学修饰纯化后的小麦酯酶,并考察修饰酶的酶学性质。方法:分别采用高碘酸钠和三聚氯氰活化右旋糖酐和mPEG,得到修饰的小麦酯酶,通过红外光谱表征修饰酶基团变化,测试修饰酶的反应动力学参数,并考察温度及pH值对修饰酶活力的影响。结果:修饰后的酶与纯化酶相比,修饰酶对底物乙酸-1-萘酯的亲和力增强,并保留了大部分酶的活力,右旋糖酐修饰酶活保持率在67.1%,mPEG修饰酶的酶活保持率达到87.7%。另外,右旋糖酐修饰酶的最适温度和pH值分别为35℃和6.4,Km和Vmax分别为2.00mmol/L和2000μg/min,而mPEG修饰酶的最适温度和pH值为35℃和6.8,Km和Vmax为1.25mmol/L和2500μg/min。两种修饰酶在耐热性、耐酸碱性等方面都优于纯化酶,mPEG修饰酶的最适pH值发生改变。结论:修饰酶较纯化酶更稳定,具有一定的实用意义。

关键词: 小麦酯酶, 右旋糖酐, 单甲氧基聚乙二醇, 酶活力, 稳定性

Abstract:

Objective: To modify purified wheat esterase with dextran and methoxy polyethyleneglycol (mPEG), and characterize
the modified enzymes. Methods: Dextran and mPEG were activated by sodium periodate and trimer cyanuric chloride, respectively,
before being used to prepare the modified wheat esterases. Changes in the active groups in the modified enzyme molecules
were described through infrared spectroscopy, and their kinetic parameters and the effects of temperature and pH on the modified
enzyme activities were investigated. Results: In comparison with the native enzyme, the modified enzyme had better affinity for the substrate
alpha-naphthyl acetate, and retained the majority of enzyme activity. The residual activity of dextran-modified enzyme was 67.1%,
and the mPEG modified enzyme retained 87.7% of the original activity. In addition, thermal stability and acid-base stability of the two
modified enzymes were better than those of the native one, and the optimal pH of the mPEG-modified enzyme was changed. Conclusion:
The modified enzymes have more stability than the native enzyme and thus are of important practical significance.

Key words: wheat esterase, dextran, methoxy polyethyleneglycol, enzyme activity, stability

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