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生物质化学工程 ›› 2013, Vol. 47 ›› Issue (1): 27-32.doi: 10.3969/j.issn.1673-5854.2013.01.004

• 研究报告 • 上一篇    下一篇

里氏木霉β-木糖苷酶的分离纯化、酶学性质及水解机理研究

江小华, 朱均均, 余世袁, 勇强   

  1. 南京林业大学 化学工程学院, 江苏 南京 210037
  • 收稿日期:2012-11-23 修回日期:1900-01-01 出版日期:2013-01-30 发布日期:2013-01-30
  • 通讯作者: 勇强,男,教授,博士生导师,主要从事生物质资源生物降解与转化的研究;E-mail:swhx@njfu.com.cn。

Purification, Characterization and Hydrolysis Mechanism of β-Xylosidase from Trichoderma reesei

JIANG Xiao-hua, ZHU Jun-jun, YU Shi-yuan, YONG Qiang   

  1. College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
  • Received:2012-11-23 Revised:1900-01-01 Online:2013-01-30 Published:2013-01-30

摘要: 通过硫酸铵沉淀、超滤脱盐、离子交换层析、凝胶过滤层析等手段,从里氏木霉(Trichoderma reesei)Rut C-30木聚糖酶粗酶液中分离纯化得到分子质量110.8 ku、比活力为61.99 IU/mg的电泳纯β-木糖苷酶。酶学性质研究结果表明:该酶反应以温度60 ℃、pH值3.5为宜,在60 ℃以下、pH值3.0~8.0酶活性稳定,且该酶作用于对硝基苯基-β-D-木糖苷的Km值和Vmax值分别为0.29 μmol/mL和169.99 IU/mg。酶水解机理研究结果表明,该酶从低聚木糖的非还原性末端切断β-1,4-糖苷键释放出木糖,其最适作用底物是短链的低聚木糖,随着低聚木糖碳链的增长,酶作用效率逐渐下降,而对木聚糖几乎不降解。

关键词: 里氏木霉, β-木糖苷酶, 分离纯化, 酶水解

Abstract: Using ammonium sulfate precipitation, ultrafiltration desalination, ion-exchange and gel filtration column chromatography, a β-xylosidase with molecular weight of 110.8 ku and specific activity of 61.99 IU/mg was purified to homogeneity from culture xylanase solution of Trichoderma reesei Rut C-30. Results of enzymatic properties showed that the optimal reaction condition of the enzyme was: pH value of 3.5; reaction temperature of 60 ℃. The enzyme was stable below 60 ℃ and pH value ranges from 3.0 to 8.0. It had a Km value of 0.29 μmol/mL and Vmax value of 169.99 IU/mg by using p-nitrophenyl-β-D-xylopyranoside as the substrate. Results of enzymatic hydrolysis mechanism indicated that β-xylosidase released xylose from non-reducing ends of xylooligosaccharides by cutting off β-1,4-glycosidic bond. The optimum substrate of β-xylosidase was short-chain xylooligosaccharides. With chain length of xylooligosaccharides increased, the enzyme hydrolysis efficiency decreased gradually and xylan was hardly to be degraded.

Key words: Trichoderma reesei, β-xylosidase, purification, enzymatic hydrolysis

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