Xue Qing, Wei Zhuan, Sun Wenjing, Cui Fengjie, Yu Silian, Zhou Qiang, Liu Jingze
School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
Parchn Sodium Isovitamin C Co. Ltd, Dexing 334221, China.
Molecules. 2015 Jan 8;20(1):846-62. doi: 10.3390/molecules20010846.
Glucose dehydrogenase (GlcDH) is the rate-limiting catalyst for microbial conversion of glucose to the important organic acid 2-ketogluconic acid (2KGlcA). In this study, a D-glucose dehydrogenase was purified from the industrial 2KGlcA producer Arthrobacter globiformis C224. After four purification steps, the GlcDH was successfully purified over 180 folds and specific activity of 88.1 U/mg. A single protein band of 87 kDa was detected by SDS-PAGE. The purified GlcDH had the broad substrate specificity with the Km values for D-glucose, D-xylose, D-galactose and maltose of 0.21 mM, 0.34 mM, 0.46 mM and 0.59 mM, respectively. The kinetic studies proved that A. globiformis GlcDH followed the ping-pong kinetic mechanism. The GlcDH showed an optimum catalytic activity at pH 5.0 and 45 °C with the stable activity at temperature of 20-40 °C and pH of 6.0-7.0. Organic solvents, metal ions or EDTA could significantly influence the GlcDH activity to different degrees.
葡萄糖脱氢酶（GlcDH）是微生物将葡萄糖转化为重要有机酸2-酮基葡萄糖酸（2KGlcA）的限速催化剂。在本研究中，从工业生产2KGlcA的球形节杆菌C224中纯化出一种D-葡萄糖脱氢酶。经过四个纯化步骤，GlcDH成功纯化了180多倍，比活性为88.1 U/mg。通过SDS-PAGE检测到一条87 kDa的单一蛋白条带。纯化后的GlcDH具有广泛的底物特异性，对D-葡萄糖、D-木糖、D-半乳糖和麦芽糖的Km值分别为0.21 mM、0.34 mM、0.46 mM和0.59 mM。动力学研究证明，球形节杆菌GlcDH遵循乒乓动力学机制。GlcDH在pH 5.0和45°C时表现出最佳催化活性，在20-40°C的温度和6.0-7.0的pH值下具有稳定的活性。有机溶剂、金属离子或EDTA会在不同程度上显著影响GlcDH的活性。
