The study of food-grade induced expression and enzymatic properties of L-Arabinose Isomerase from Lactobacillus plantarum WU14 with high D-tagatose yield
The study of food-grade induced expression and enzymatic properties of L-Arabinose Isomerase from Lactobacillus plantarum WU14 with high D-tagatose yield
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高D-塔格糖产量植物乳杆菌WU14中L-阿拉伯糖异构酶的食品级诱导表达和酶学特性研究
DOI：
10.4236/fns.2016.74034
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Bo Xu
中科院分区：
文献类型：
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作者：
Xiaoyu Chang;Bi Ying;Yanli Zhang;Huifang Cao;Tong Zhou;Ping'an Zhong;Bo Xu
l -阿拉伯糖异构酶（L-AI）是d -塔格糖生物法d -半乳糖异构化的关键酶。本研究鉴定出d -塔格糖产率较高的植物乳杆菌WU14，该植物乳杆菌是从酸菜中的乳酸菌中分离得到的。d -塔格糖产率较高的植物乳杆菌WU14在最适温度60℃、pH 7.17、底物浓度0.8 mol/L条件下，粗L-阿拉伯糖异构酶活性为13.95 U/mL， 28 h转化率可达56.12%。研究了植物乳杆菌WU14的l -阿拉伯糖异构酶的蛋白质结构和特异性。结果表明，l -阿拉伯糖异构酶主要由α螺旋和随机螺旋组成。将重组L-AI基因插入到食品级表达载体中。pRNA48在L. lactis NZ9000中成功表达。12 h后，当nisin诱导浓度达到30 ng/mL时，目标蛋白表达量达到最大，60℃条件下重组菌粗酶活性达到6.21 U/mL。在此条件下重组乳杆菌NZ9000/pRNA48-L-AI的最佳转化率可达39.21%。温度为50℃，pH为7.17，d -半乳糖浓度为0.6 mol/L。
L-arabinose isomerase (L-AI) is the key enzyme for D-galactose isomerization of D-tagatose by biological.method. In this research, Lactobacillus plantarum WU14 with high D-tagatose yield was identified as Lactobacillus plantarum was isolated from the number of lactic acid bacteria from pickled vegetables. The crude L-arabinose isomerase activity of Lactobacillus plantarum WU14 with high D-tagatose yield was 13.95 U/mL under the optimal temperature 60˚C, pH 7.17 and substrate concentration 0.8 mol/L, and the conversion rate of 56.12% could be gained after 28 hours. Protein structure and specific of L-Arabinose Isomerase of Lactobacillus plantarum WU14 were researched. The results showed that L-arabinose isomerase is mainly composed of alpha helix and random coil. Then the recombinant L-AI gene was inserted into the food-grade expression vector.pRNA48 and expressed in L. lactis NZ9000 successfully. The target protein expression reached the maximum amount when the induced concentration of nisin reaches 30 ng/mL after 12 h. And the crude enzyme activity of recombinant bacteria reached 6.21 U/mL under 60˚C. Otherwise the optimal conversion rate recombinant of L. lactis NZ9000/pRNA48-L-AI can reach 39.21% under the.temperature of 50˚C, pH 7.17 and D-galactose concentration was 0.6 mol/L.