食品工业科技2012，Vol.33Issue(4)：108-113,6.
新型碱性低分子量β-葡萄糖苷酶基因的分离与酶学性质研究
Gene isolation and characterization of a novel alkaline β-glucosidase with low molecular mass
摘要
Abstract
Objective：Intended to obtain a gene encoding β-glucosidase applied for constructing engineering bacterium,and analyzed the enzymic properties of the β-glucosidase.Method：Using the metagenomic library and plate screening method for screening clones generating β-glucosidase,and the clones were validated by sequencing.Furthermore,multiple amino acid sequence alignment was checked for the inserted sequence.The characteristices of the enzyme product by E.coli expression system were measured under different conditions,such as different temperature,substrates.Result：A β-glucosidase-encoding gene fragment from the microbes in rabbit cecum was cloned,named nglu 07.The putative protein with molecular mass of 6.68ku was encoded by the gene（180bp）.An incomplete metallo-dependent_hydrolases superfamily domain was identified through the on line NCBI with BLASTP program and SMART online prediction.The amino acid multiple alignment showed that nglu 07 was similar to the glycoside hydrolase familyⅠ β-glucosidases and demonstrated that the Glu4,Tyr47 may be the predicted active site and binding site,respectively.The low sequence similarily with other β-glucosidases denoted that nglu 07 was likely to a novel member of glycoside hydrolase family.Analysis of the β-glucosidases activity showed that its optimum temperature and pH were 50℃ and pH 10.0,respectively.The crude enzyme activity of fermentingliquor was about 8.12U/mL.Conclusion：We successfully isolated a β-glucosidases-encoding gene.The enzyme showed the high-alkaline-tolerance characteriaztion and temperature stability.Taking these advantages,the novel alkaline β-glucosidase could be implied in the food,juice,detergent and recycled paper industries.关键词
宏基因组/文库/新型β-葡萄糖苷酶/低分子量/酶学性质Key words
metagenome/library/novel β-glycosidase/low molecular mass/character of enzymology分类
轻工纺织引用本文复制引用
马振刚,唐婧,马淑华,张时恒,贾俊杰,李田,周泽扬..新型碱性低分子量β-葡萄糖苷酶基因的分离与酶学性质研究[J].食品工业科技,2012,33(4):108-113,6.基金项目
国家自然科学基金重点项目 （）
高等学校学科创新引智计划 （）
西南大学研究生科技创新基金项目 （）
