Activating Phosphoenolpyruvate Carboxylase and Phosphoenolpyruvate Carboxykinase in Combination for Improvement of Succinate Production
Activating Phosphoenolpyruvate Carboxylase and Phosphoenolpyruvate Carboxykinase in Combination for Improvement of Succinate Production
复制标题
联合激活磷酸烯醇丙酮酸羧化酶和磷酸烯醇丙酮酸羧激酶以提高琥珀酸产量
DOI：
10.1128/aem.00826-13
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发表时间：
2013-08-01
影响因子：
4.4
通讯作者：
Zhang, Xueli
中科院分区：
文献类型：
--
作者：
Tan, Zaigao;Zhu, Xinna;Zhang, Xueli
摘要磷酸烯醇式丙酮酸（PEP）羧化是大肠杆菌生产琥珀酸的重要步骤。PEP羧化作用由两种酶，PEP羧化酶（PPC）和PEP羧激酶（PCK）负责。PPC具有较高的底物亲和力和催化速度，但浪费了PEP的高能量。PCK具有低的底物亲和力和催化速度，但可以保存PEP的高能量用于ATP的形成。在这项工作中，ppc和pck基因的表达进行调制，具有不同强度的多个调节部分，以研究PPC或PCK活性与琥珀酸生产之间的关系。PCK活性与琥珀酸产量呈正相关。相反，只有当PPC活性在一定范围内时，PPC活性和琥珀酸产量之间才呈正相关;过量的PPC活性降低了细胞生长和琥珀酸形成的速率。这两种酶也被联合激活，以发挥各自的优势，提高琥珀酸生产。结果表明，PPC和PCK在提高琥珀酸产量方面具有协同效应。
ABSTRACT Phosphoenolpyruvate (PEP) carboxylation is an important step in the production of succinate by Escherichia coli. Two enzymes, PEP carboxylase (PPC) and PEP carboxykinase (PCK), are responsible for PEP carboxylation. PPC has high substrate affinity and catalytic velocity but wastes the high energy of PEP. PCK has low substrate affinity and catalytic velocity but can conserve the high energy of PEP for ATP formation. In this work, the expression of both the ppc and pck genes was modulated, with multiple regulatory parts of different strengths, in order to investigate the relationship between PPC or PCK activity and succinate production. There was a positive correlation between PCK activity and succinate production. In contrast, there was a positive correlation between PPC activity and succinate production only when PPC activity was within a certain range; excessive PPC activity decreased the rates of both cell growth and succinate formation. These two enzymes were also activated in combination in order to recruit the advantages of each for the improvement of succinate production. It was demonstrated that PPC and PCK had a synergistic effect in improving succinate production.