Interdisciplinary Program for Biochemical Engineering and Biotechnology, Seoul National University, Seoul 151-742, South Korea.
Bioprocess Biosyst Eng. 2010 Jan;33(1):71-8. doi: 10.1007/s00449-009-0365-2.
Five recombinant Escherichia coli extracts harboring overexpressed galactokinase, galactose-1-phosphate uridyltransferase, UDP-glucose pyrophophorylase, UMP kinase, and acetate kinase (AK) were utilized for the production of UDP-galactose (UDP-Gal). We analyzed the parameters which limit the yield of UDP-Gal in the reaction, and the reaction was optimized by increasing the concentration of AK. AK was used for the ATP regeneration as well as the conversion of UDP to UTP. The activities of four overexpressed enzymes were identically fixed, and then we increased the activity of AK to 20 times higher than others. The extracts catalyzed the production of UDP-Gal from UMP (10 mM), galactose (12 mM), ATP (1 mM), and acetyl phosphate (40 mM). As the result of the reaction, the conversion yield of UDP-Gal reached to 95% from 10 mMUMP.
利用 5 种含有过量表达的半乳糖激酶、半乳糖-1-磷酸尿苷酰转移酶、UDP-葡萄糖焦磷酸化酶、UMP 激酶和乙酰激酶（AK）的重组大肠杆菌提取物来生产 UDP-半乳糖（UDP-Gal）。我们分析了限制反应中 UDP-Gal 产量的参数，并通过增加 AK 的浓度对反应进行了优化。AK 用于 ATP 的再生以及 UDP 向 UTP 的转化。固定四种过表达酶的活性，然后将 AK 的活性提高到比其他酶高 20 倍。提取物从 UMP（10 mM）、半乳糖（12 mM）、ATP（1 mM）和乙酰磷酸（40 mM）催化 UDP-Gal 的生成。反应的结果是，从 10 mM UMP 转化生成 UDP-Gal 的转化率达到了 95%。
