Ding Qingbao, Oua Ling
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237. China.
Curr Pharm Des. 2017 Oct 24. doi: 10.2174/1381612823666171024155247.
Nucleoside 5'-triphosphates (NTPs) play an important role in cells in the transfer of phosphate groups or bioenergy. In vivo, they are ready to be produced, regenerated and consumed in different kinds of metabolic pathways, and their concentrations are strictly controlled. NTPs are useful reagents that take part in many biosynthetic processes. However, NTPs are expensive and unstable, which greatly increases the cost of the final product if a large amount of NTPs is used directly in biosynthesis. Furthermore, during reactions, NTPs degrade into NDPs and need to be separated from the reaction mixture, making the operation complicated. Therefore, NTPs are normally regenerated from NDPs, and only very few NTPs are used in the reaction.
Mechanisms of NTP regeneration were analysed, and their applications in the biosynthesis of nucleotides and their derivates were described. Basically, NTP regeneration involves isolated enzyme systems and whole-cell systems.
As one type of cofactor regeneration, NTPs can be effectively regenerated by acetate kinase, pyruvate kinase, and polyphosphate kinase from acetyl phosphate, phosphoenol pyruvate, and polyphosphate, respectively, or by whole cells of yeast and Corynebacterium ammoniagenes from simple carbohydrates and phosphate. The NTP-regeneration method is selected primarily due to the main reaction that it is being coupled with. The cost of phosphate donors and the convenience of integration with the main process should be considered.
Significant advances have been made when NTP regeneration is coupled with other biosynthetic processes, especially in the preparation of nucleotides, 2'-deoxynucleotides, sugar-nucleotides and their derivatives.
核苷5'-三磷酸（NTPs）在细胞中磷酸基团转移或生物能量传递方面发挥着重要作用。在体内，它们随时准备在各种代谢途径中产生、再生和消耗，其浓度受到严格控制。NTPs是参与许多生物合成过程的有用试剂。然而，NTPs价格昂贵且不稳定，如果在生物合成中直接大量使用，会大大增加最终产品的成本。此外，在反应过程中，NTPs会降解为二磷酸核苷（NDPs），需要从反应混合物中分离出来，这使得操作变得复杂。因此，NTPs通常从NDPs再生而来，反应中仅使用极少的NTPs。
分析了NTP再生的机制，并描述了其在核苷酸及其衍生物生物合成中的应用。基本上，NTP再生涉及分离酶系统和全细胞系统。
作为一种辅因子再生方式，NTPs可分别通过乙酸激酶、丙酮酸激酶和多磷酸激酶从乙酰磷酸、磷酸烯醇丙酮酸和多磷酸中有效再生，或者通过酵母和产氨棒杆菌的全细胞从简单碳水化合物和磷酸盐中再生。NTP再生方法的选择主要取决于与之偶联的主要反应。应考虑磷酸盐供体的成本以及与主要过程整合的便利性。
当NTP再生与其他生物合成过程偶联时，尤其是在制备核苷酸、2'-脱氧核苷酸、糖核苷酸及其衍生物方面，已取得了显著进展。
