Dekker K, Sugiura A, Yamagata H, Sakaguchi K, Udaka S
Faculty of Agriculture, Nagoya University, Japan.
Appl Microbiol Biotechnol. 1992 Mar;36(6):727-32. doi: 10.1007/BF00172183.
The xylose (glucose) isomerase from the thermophile Thermus thermophilus seems to have potential for the development of new isomerization processes using high temperatures and slightly acidic pH. The isomerase has an optimum temperature at 95 degrees C, and is also very stable at high temperatures. The optimum pH is around 7.0, close to where by-product formation is minimal. Since Thermus produces only a little of this useful isomerase, the production of the cloned gene in Escherichia coli and Bacillus brevis were compared. Especially B. brevis was able to produce the isomerase efficiently, more than 1 g/l, in spite of the high G + C content (67%) of the Thermus gene, and the presence of codons not frequently used in E. coli or B. brevis.
嗜热栖热菌（Thermus thermophilus）的木糖（葡萄糖）异构酶似乎具有开发利用高温和微酸性pH值的新型异构化工艺的潜力。该异构酶的最适温度为95℃，在高温下也非常稳定。最适pH值约为7.0，接近副产物形成最少的范围。由于栖热菌仅产生少量这种有用的异构酶，因此比较了该克隆基因在大肠杆菌和短短芽孢杆菌中的表达。尽管栖热菌基因的G + C含量很高（67%），且存在大肠杆菌或短短芽孢杆菌中不常用的密码子，但短短芽孢杆菌仍能够高效表达该异构酶，产量超过1 g/L。
