食品科学 ›› 2012, Vol. 33 ›› Issue (11): 205-209.doi: 10.7506/spkx1002-6630-201211044

• 生物工程 • 上一篇    下一篇

热稳定酸性β - 葡萄糖苷酶的分离纯化及其酶学性质

陈今朝1,王剑锋2,*,王慧超1,谭永忠1   

  1. 1.长江师范学院生命科学与技术学院 2东华理工大学生物系
  • 出版日期:2012-06-15 发布日期:2012-07-27
  • 基金资助:
    重庆市科技攻关计划项目(CSTC,2011AC1004)

Purification and Characterization of Thermostable Acidic β-Glucosidase from Aspergillus niger L.

CHEN Jin-zhao1,WANG Jian-feng2,*,WANG Hui-chao1,TAN Yong-zhong1   

  1. (1. Life Science and Technology Institute, Yangtze Normal University, Chongqing 408100, China ; 2. Department of Biology, East China Institute of Technology, Fuzhou 344000, China)
  • Online:2012-06-15 Published:2012-07-27

摘要: 耐酸性黑曲霉菌株Aspergillus niger L.的菌丝体破碎液依次经过乙醇沉淀、离子交换层析和凝胶过滤等步骤处理,获得电泳纯的β-葡萄糖苷酶,SDS-PAGE显示其分子质量为125.7kD。β-葡萄糖苷酶水解对硝基苯-β-D-吡喃葡萄糖苷的最适pH值为3.0~4.0,最适温度为70℃,表观米氏常数(Km)值为2.35mmol/L,表观kcat/Km值为2.99×104L/(mol ·s);水解京尼平苷、水杨苷的表观kcat/Km值分别是1.26×104、1.37×104L/(mol ·s);水解活性受Mn2+的显著激活和Fe2+、Zn2+、Cu2+等离子的微弱抑制。该酶活性在pH2.0~8.3保持稳定;酶在65℃时保温60min,残余酶活达到了85%,是一种热稳定酸性β-葡萄糖苷酶。

关键词: 胞内酶, 乙醇沉淀, 对硝基苯-β-D-吡喃葡萄糖苷, 京尼平苷, β-葡萄糖苷酶

Abstract: In this study, an acidic β-glucosidase (BGL) was purified from acid-tolerant Aspergillus niger L. mycelia by ethanol precipitation, DEAE-Sepharose column chromatography and Sephadex G-100 column chromatography. SDS-PAGE showed that the molecular weight of the enzyme was 125.7 kD. Further characterization revealed that it had maximal hydrolytic activity on p-nitrophenyl-β-D-glucopyranoside (pNPG) at pH 3.0 - 4.0 and 70 ℃ with a Km of 2.35 mmol/L and a kcat/Km of 2.99 × 104 mol/L ·s. The kcat/Km values for hydrolyzing geniposide and salicin were 1.26 × 104 L/(mol ·s) and 1.37 × 104 L/(mol ·s), respectively. The hydrolytic activity was activated obviously by Mn2+ but inhibited faintly by Fe2+, Zn2+ and Cu2+. The BGL was highly stable at pH 2.0 - 8.5, and 85% of its original activity could be maintained after 60 min of heat treatment at 65 ℃. Thus, the enzyme was highly stable to heat.

Key words: intracellular enzyme, ethanol precipitation, p-nitrophenyl-β-D-glucopyranoside, genipin, β-glucosidase

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