通过基因挖掘的方法从NCBI 数据库中筛选得到一株嗜热的葡萄糖异构酶（GI）产生菌株Thermotoga petrophila RKU-1，化学合成该酶的基因并在大肠杆菌E. coli BL21（DE3）中进行可溶性表达。重组葡萄糖异构酶经过Ni-NTA 柱亲和层析分离纯化后，对纯酶进行SDSPAGE检测，结果显示为单一条带，其分子量大小为50.8 kDa。测定了该重组酶对底物D-葡萄糖的活力为19.8 U/mg，并对其酶学性质进行了表征。该酶最适温度和pH 分别为85 ℃和7.0，Co2+对催化活力起着非常重要的作用， 对底物D-葡萄糖的Km值和Vmax值分别为373 mmol/L和13.4 U/mg。在最适条件下，反应在4 h 内达到平衡，果糖得率最高达到53.8%。

A hyperthermophilic glucose isomerase from Thermotoga petrophila RKU-1 (TPGI) was screened by genome mining from NCBI database. The gene of TPGI was synthesized and expressed as a soluble protein in E. coli BL21 (DE3). The recombinant enzyme was purified by Ni-NTA affinity chromatography. The SDS-PAGE analysis of the purified TPGI revealed a single band with a molecular weight of around 50.8 kDa. The specific activity of the recombinant TPGI to D -
glucose was 19.8 U/mg. The enzyme exhibited its maximum activity at 85 ℃, pH 7.0 and showed significant dependence on Co2+. The Km and Vmax to substrate D-glucose were 373 mmol/L and 13.4 U/ mg, respectively. The yield of D-fructose reached 53.8% and the isomerization gradually maintained
equilibrium after 4 h under the optimum conditions.