Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua Donglu, Haidian District, Beijing, 100083, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Engineering, China Agricultural University, No.17 Qinghua Donglu, Haidian District, Beijing, 100083, China.
Appl Biochem Biotechnol. 2021 May;193(5):1482-1495. doi: 10.1007/s12010-021-03487-y. Epub 2021 Jan 23.
D-Mannose isomerase can reversibly catalyze D-fructose to D-mannose which has various beneficial effects. A novel D-mannose isomerase gene (PsMIaseA) from Pseudomonas syringae was cloned and expressed in Escherichia coli. The recombinant D-mannose isomerase (PsMIaseA) showed the highest amino acid sequence homogeneity of 50% with ManI from Thermobifda fusca. PsMIaseA was purified through Ni-NTA chromatography, and its specific activity was 818.6 U mg. The optimal pH and temperature of PsMIaseA were pH 7.5 and 45 °C, respectively. The enzyme was stable within a wide pH range from 5.0 to 10.0. It could efficiently convert D-fructose to D-mannose without any metal ions. When PsMIaseA was incubated with 600 g/L D-fructose for 6 h, the space-time yield of D-mannose reached 27.2 g L h with a maximum conversion ratio of 27%. Therefore, the D-mannose isomerase may be suitable for green production of D-mannose.
D-甘露糖异构酶能够可逆地催化 D-果糖转化为 D-甘露糖，具有多种有益作用。本研究从丁香假单胞菌中克隆并在大肠杆菌中表达了一种新型 D-甘露糖异构酶基因（PsMIaseA）。重组 D-甘露糖异构酶（PsMIaseA）与来自Thermobifda fusca 的 ManI 的氨基酸序列同源性最高，为 50%。PsMIaseA 通过 Ni-NTA 层析进行纯化，其比活为 818.6 U mg。PsMIaseA 的最适 pH 和温度分别为 7.5 和 45°C。该酶在 pH 5.0 至 10.0 的较宽范围内稳定。它可以在没有任何金属离子的情况下有效地将 D-果糖转化为 D-甘露糖。当 PsMIaseA 与 600 g/L D-果糖孵育 6 h 时，D-甘露糖的时空产率达到 27.2 g L h，转化率最高可达 27%。因此，D-甘露糖异构酶可能适合 D-甘露糖的绿色生产。
