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^–1. 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^–1 h^–1 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 -fructose到d甘露糖，其具有各种有益的效果。从丁香假单胞菌中克隆出一个新的d-甘露糖异构酶基因( PsMIaseA )，并在大肠杆菌中表达。重组d-甘露糖异构酶( Ps MIaseA)与来自Thermobifda fusca的ManI显示出最高的50%的氨基酸序列同质性。Ps MIaseA经Ni-NTA层析纯化，比活为818.6 U mg ^–1。Ps的最佳pH值和温度MIaseA 的 pH 值分别为 7.5 和 45°C。该酶在 5.0 至 10.0 的宽 pH 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。当诗MIaseA用600g温育/ L ð -fructose 6小时，的时空产率d甘露糖达到27.2克L- ^-1 ħ ^-1为27％的最大转化率。因此，d甘露糖异构酶可以是适合于绿色生产的d甘露糖。