Characterization of a novel highly thermostable esterase from Gram-positivesoil bacterium Streptomyces lividans TK64

【作者】 王宝娟； 王敖； 曹正宇； 朱国萍；

【机构】 安徽师范大学分子生物学与生物技术研究所；

【摘要】 Esterase is one of the most important biocatalysts and widely used in modern industries.A novel esterase gene(estW)was cloned from Streptomyces lividans TK64,which encodes EstW containing 289 amino acids.This protein was overexpressed in Escherichia coli and purified.The substrates catalyzed by EstW were identified through the hydrolysis of various p-nitrophenyl esters(acetate,butyrate,caproate,caprylate and myristate).The p-nitrophenyl acetate(pNPA2)was the best substrate for EstW.The maximal activity of EstW was found at pH 8.0 and 50°C with pNPA2 as a substrate.Activation energy(E_a)of the enzyme was calculated to be 9.12 kcal/mol.The half-life of EstW was approximately 12.5 hours at 95℃.To the best of our knowledge,it is the highest thermostable esterase among all the lipolytic enzymes from Streptomyces and was even more thermostable than many enzymes from thermophiles.The activity of EstW was cation-independent and showed high tolerance to several detergents.Due to high activity and affinity toward short-chain esters(C2-C4),EstW may have potential for use in food processing industry,such as flavor synthesis.更多还原

【Abstract】 Esterase is one of the most important biocatalysts and widely used in modern industries.A novel esterase gene(estW) was cloned from Streptomyces lividans TK64,which encodes EstW containing 289 amino acids.This protein was overexpressed in Escherichia coli and purified.The substrates catalyzed by EstW were identified through the hydrolysis of various p-nitrophenyl esters(acetate,butyrate,caproate,caprylate and myristate).The p-nitrophenyl acetate(pNPA2) was the best substrate for EstW.The maximal activity of EstW was found at pH 8.0 and 50 ℃ with pNPA2 as a substrate.Activation energy(E_a) of the enzyme was calculated to be 9.12 kcal/mol.The half-life of EstW was approximately 12.5 hours at 95 ℃.To the best of our knowledge,it is the highest thermostable esterase among all the lipolytic enzymes from Streptomyces and was even more thermostable than many enzymes from thermophiles.The activity of EstW was cation-independent and showed high tolerance to several detergents.Due to high activity and affinity toward short-chain esters(C2-C4),EstW may have potential for use in food processing industry,such as flavor synthesis.更多还原