National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Xiqi Road 32#, Tianjin Airport Economic Area, Tianjin 300308, People's Republic of China.
Biotechnol Lett. 2012 Oct;34(10):1901-6. doi: 10.1007/s10529-012-0986-4. Epub 2012 Jul 4.
The D-psicose 3-epimerase (DPE) gene from Ruminococcus sp. was cloned and overexpressed in Escherichia coli. The recombinant protein was purified and characterized. It was optimally active at pH 7.5-8.0 and 60 °C. Activity was not dependent on the presence of metal ions; however, it became more thermostable with added Mn(2+). The K (m) of the enzyme for D-psicose (48 mM) was lower than that for D-tagatose (230 mM), suggesting that D-psicose is the optimum substrate. More importantly, the thermostability of the novel DPE from Ruminococcus is the strongest among all of the D-psicose and D-tagatose 3-epimerases and may be suitable for the industrial production of D-psicose from fructose.
从瘤胃球菌中克隆并在大肠杆菌中过表达了 D-阿洛酮糖 3-差向异构酶（DPE）基因。对重组蛋白进行了纯化和表征。它在 pH7.5-8.0 和 60°C 下具有最佳活性。该酶的活性不依赖于金属离子的存在；然而，添加 Mn(2+)后其热稳定性更高。该酶对 D-阿洛酮糖（48mM）的 K(m)低于 D-塔格糖（230mM），表明 D-阿洛酮糖是最佳底物。更重要的是，来自瘤胃球菌的新型 DPE 的热稳定性在所有 D-阿洛酮糖和 D-塔格糖 3-差向异构酶中是最强的，可能适合从果糖工业生产 D-阿洛酮糖。
