文献类型： 外文期刊

作者： Lu Yang ¹ ; Liu Xiang-guo ¹ ; Yu Ying ¹ ; Qu He-zhi ¹ ; Yang Shuo ¹ ; Ning Bo ¹ ; Wang Xiao-ping ¹ ; Hao Dong-yun ² ;

作者机构： 1.Jilin Univ, Key Lab Mol Enzymol & Engn, Minist Educ, Changchun 130021, Peoples R China

2.Jilin Univ, Coll Life Sci, Changchun 130012, Peoples R China

3.Jilin Acad Agr Sci, Biotechnol Res Ctr, Changchun 130033, Peoples R China

关键词： Alkaline esterase;Enzymatic characterization;Metagenome

期刊名称：CHEMICAL RESEARCH IN CHINESE UNIVERSITIES （ 影响因子：1.307； 五年影响因子：0.979 ）

ISSN： 1005-9040

年卷期： 2010 年 26 卷 4 期

页码：

收录情况： SCI

摘要： The development of industrial biotechnology has created an increasing demand for alkaline lipolytic enzymes with functional diversity. In this study, an alkaline soil metagenomic library was constructed to search for new lipolytic enzymes. Two novel gene encoded alkaline esterases(designated as estA and estB) were isolated by functional screening from the library. The estA gene consisted of 834 bp and coded for 277 amino acids with a molecular mass of 29998. Amino acid sequence homology analysis indicates that EstA belongs to alpha/beta hydrolase fold family 4.4(abH4.4), with EstA being the smallest member of that family yet reported. The estB gene consisted of 1185 bp and encoded 394 amino acids with a theoretical molecular mass of 40090. Its conserved domain analysis shows that EstB belongs to the GDSL hydrolase superfamily. Both EstA and EstB exhibit only moderate identity(<38%) in amino acid sequence to the known lipolytic enzyme genes in the database. The two genes were respectively expressed in Escherichia coli and the protein products were purified for functional characterization. While the expressed EstA did not exhibit the functional properties that were superior to those of other esterases previously reported, the EstB was stable at temperature up to 45 degrees C and its maximum activity was measured to be 53.6 U/mg at pH=10. Both the enzymes have further enriched the diversity of the lipolytic enzymes database and also appear to be promising biocatalysts for potential biotechnological application.