米曲霉谷氨酰胺合成酶基因（AoglnAI）在大肠杆菌中的表达和酶学特性研究

摘要

将人工合成的米曲霉谷氨酰胺合成酶基因（AoglnAI）在大肠杆菌中表达，通过谷氨酰胺营养缺陷型菌株功能基因互补进行了试验，并利用亲和层析法对重组酶进行纯化。结果表明：重组酶分子质量为40.1 kD，酶的最适反应温度为30℃，最适 pH 为7.0。重组酶对底物谷氨酸钠、氨、ATP 的 Km 值分别为9.10 mmol/L、2.05 mmol/L、2.49 mmol/L。重组酶的酶学特性与非重组酶有一定的差异。%The synthetic glutamine synthetase gene(AoglnAI)of Aspergillus oryzae was expressed in Esche-richia coli,and it was verified by functional gene complementation of glutamine auxotrophic strain.The recombi-nant enzyme was purified by affinity chromatography.The results showed that the molecular mass of recombinant enzyme was 40.1 kD.The enzyme’s optimal reaction temperature was 30 ℃,the optimal pH was 7.0.The Km of recombinant enzyme to the substrate glutamate,ammonia,ATP were 9.10,2.05,2.49 mmol/L,respectively.The enzymatic characteristics of recombinant enzyme had a certain differences with non recombinant enzyme.