从米氏游动放线菌中鉴定出一种重组 l-核酮糖异构酶，并将其用于 l-核酮糖的生产。
Characterization of a recombinant l-ribose isomerase from Mycetocola miduiensis and its application for the production of l-ribulose.
机构信息
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu, 214122, China; Synergetic Innovation Center of Food Safety and Quality Control of Jiangsu Province, Wuxi 214122, China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu, 214122, China; Synergetic Innovation Center of Food Safety and Quality Control of Jiangsu Province, Wuxi 214122, China.
出版信息
Enzyme Microb Technol. 2020 Apr;135:109510. doi: 10.1016/j.enzmictec.2020.109510. Epub 2020 Jan 13.
An enzyme, l-ribose isomerase (l-RI), mostly catalyzes the isomerization of l-ribose and l-ribulose. These so-called rare sugars are essential for the treatment of cancer and other viral diseases. In the present study, l-ribose isomerase produced from a bacterium, Mycetocola miduiensis (Mm-LRIse), by using l-ribose as a carbon source. The recombinant l-ribose isomerase gene was cloned and overexpressed from M. miduiensis and purified with an exclusive band of 32 kDa by nickel-affinity chromatography. This gene possessed 267 amino acids protein having an estimated molecular weight of 29,568.17 Da. The native molecular weight of Mm-LRIse estimated by HPLC was 134.84 kDa. The recombinant l-ribose isomerase was highly active in sodium phosphate (50 mM) buffer at 40 °C and pH 7.5, showing the specific activity up to 47.40 U mg. Mm-LRIse showed no significant enhancement in activity with metallic ions except Mn and Co. The values of Km, K, K/Km and V of Mm-LRIse against l-ribose substrate were 42.48 mM, 9259.26 min, 217.43 min mM, and 277.78 U mg respectively. At equilibrium, the l-ribulose transformation rate was nearly 32 % (6.34 g L) using 20 g L of l-ribose. The results revealed that the Mm-LRIse enzyme has a potential for L-ribulose production from l-ribose.
一种酶，L-核糖异构酶（l-RI），主要催化 L-核糖和 L-核酮糖的异构化。这些所谓的稀有糖对于治疗癌症和其他病毒性疾病至关重要。在本研究中，使用 L-核糖作为碳源，从细菌 Mycetocola miduiensis（Mm-LRIse）中生产 L-核糖异构酶。通过镍亲和层析，从 M. miduiensis 中克隆和过表达重组 L-核糖异构酶基因，并纯化出 32 kDa 的特有条带。该基因具有 267 个氨基酸的蛋白质，估计分子量为 29568.17 Da。通过 HPLC 估算的 Mm-LRIse 的天然分子量为 134.84 kDa。重组 L-核糖异构酶在 40°C 和 pH 7.5 的磷酸钠（50 mM）缓冲液中具有很高的活性，表现出高达 47.40 U mg 的比活性。除 Mn 和 Co 外，Mm-LRIse 的活性没有明显增强金属离子。Mm-LRIse 对 L-核糖底物的 Km、K、K/Km 和 V 值分别为 42.48 mM、9259.26 min、217.43 min mM 和 277.78 U mg。在平衡时，使用 20 g L 的 L-核糖，L-核酮糖的转化率接近 32%（6.34 g L）。结果表明，Mm-LRIse 酶具有从 L-核糖生产 L-核酮糖的潜力。
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