一株嗜热菌木糖异构酶的纯化与性质研究  

Purification and Characterization of a Thermostable Xylose Isomerase Produced by the Thermophilic Bacterium Anoxybacillus flavithermus

作　　者：张波[1] 殷燕[1,2] 

机构地区：[1]北京联合大学应用文理学院 [2]北京中恒意美环境工程技术有限公司

出　　处：《食品与发酵工业》2011年第3期13-17,共5页Food and Fermentation Industries

基　　金：国家重点基础研究发展计划(973计划)项目(2007CB707805)

摘　　要：研究了1株嗜热菌（Anoxybacillus flavithermus）所产木糖异构酶的分离纯化以及酶学性质。结果表明，经硫酸铵沉淀、SephadexG-5凝胶过滤、纤维素DE-2弱阴离子交换柱和QSepharoseFastFlow强阴离子交换层析得到的木糖异构酶，分子量约为181ku，由4个相同分子量的亚基组成。酶反应的最适温度为80℃，最适为pH为7．0且最适pH范围宽泛，pH6．0-11．0酶反应活性能保持80％左右。该酶热稳定性及耐碱性能良好，70℃保温1h后酶活仍能保持近80％左右；pH5．0—8．0保温1h后酶活仍能保持近80％以上，甚至pH12．0保温1h后酶活性仍能保持40％左右。Mn2＋和Co2＋对酶活性有明显促进作用，Zn2＋、Cu2＋以及AL3＋对酶活性有一定程度的抑制。A xylose isomerase produced by thermophilic bacterium Anoxybacillus flavithermus was purified using Sephadex G -75 gel filtration,DEAE-cellulose anion exchange chromatography and Q Sepharose Fast Flow anion exchange chromatography. The estimated molecular mass of the purified xylose isomerase was 181 ku and was made up of four sub-groups. The optima temperature and pH of enzymatic reaction were 80℃ and pH 7.0, respectively. This xylose isomerase is alkali- tolerant and thermo-stable： the enzyme activity keep about 80% in 70℃ for lh and keep about 80% in pH5.0 - 8.0 for 1 h, even keep about 40% in pill2.0 for 1 h. The enzyme was mainly activated by Mn2＋ and Co2＋ but was mainly restrained by Zn2＋ , Cu2＋and AL3＋.

关 键 词：嗜热木糖异构酶 酶的纯化 酶学性质 

分 类 号：Q814.1[生物学—生物工程]