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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (20): 2390-2394. 上一篇    

研究论文

木瓜蛋白酶的化学修饰及对其酶活力的影响

薛勇   李树白   张海涛   聂华丽*    朱利民   

  1. (东华大学化学化工与生物工程学院 上海 201620)
  • 投稿日期:2008-11-27 修回日期:2009-05-04 发布日期:2009-06-02
  • 通讯作者: 薛勇 E-mail:shxueyong@gmail.com
  • 基金资助:

    国家自然科学基金(No. 50773009)；上海市科委重点基金(08JC1400600)资助项目

Chemical Modification of Papain and Effect on its Enzyme Activity

Xue, Yong    Li, Shubai       Zhang, Haitao       Nie, Huali*        Zhu, Limin*   

  1. (College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620)
  • Received:2008-11-27 Revised:2009-05-04 Published:2009-06-02

PDF

3596

被引次数

21

用不同酸酐对木瓜蛋白酶进行化学修饰, 以三硝基苯磺酸法(TNBS)测定修饰酶的平均氨基修饰度, 对修饰前后的木瓜蛋白酶分别纯化并通过UV-vis和IR对其结构进行了表征. 考察了温度、pH值和表面活性剂SDS对化学修饰的木瓜蛋白酶活力的影响, 并与天然木瓜蛋白酶进行了比较, 对天然酶和修饰酶进行了动力学研究. 结果表明, 化学修饰木瓜蛋白酶的最适反应温度为80 ℃; 最适pH值为9.0; 在SDS浓度为5 mg•mL－1时修饰酶酶活仍能保持在50%左右; 在所有酶中, 均苯四甲酸酐修饰木瓜蛋白酶的催化效率最高, 为2.442×102. 与天然木瓜蛋白酶相比, 化学修饰木瓜蛋白酶的热稳定性、耐碱性和耐洗涤性得到了显著提高.

关键词: 化学修饰, 木瓜蛋白酶, 酸酐, 动力学

Papain was modified using different anhydrides. The average ratio of modified-NH2 was tested by a trinitrobenzenesulfonic acid (TNBS) method. The native and modified papain samples were purified by dialysis and their structures were characterized by UV and IR. The factors related with the activity of the modified papain, such as temperature, pH value, kinetic constant and the concentration of SDS were studied and compared with those of the native papain. The results showed that the optimum reaction temperature and pH for modifying papain were 80 ℃ and 9.0, respectively. When the concentration of SDS was 5 mg• mL－1, about 50% of the activity of the modified papain were maintained. Among these modified enzymes, the enzyme modified with pyromellitic dianhydride was found to be best in catalytic efficiency. Compared with the native papain, the thermal stability and the resistance of modified enzyme to alkali and washing detergent were improved considerably.

Key words: chemical modification, papain, anhydride, kinetics