Glucose is metabolized through central metabolic pathways such as glycolysis and the pentose phosphate pathway (PPP) to synthesize downstream metabolites including amino acids. However, how the split ratio of carbon flux between glycolysis and PPP specifically affects the formation of downstream metabolites remains largely unclear. Here, we conducted a comprehensive metabolomic analysis to investigate the effect of the split ratio between glycolysis and the PPP on the intracellular concentration of amino acids and their derivatives in Corynebacterium glutamicum. The split ratio was varied by exchanging the promoter of a gene encoding glucose 6-phosphate isomerase (PGI). The ratio was correlated with the pgi transcription level and the enzyme activity. Concentrations of threonine and lysine-derivative 1,5-diaminopentane increased with an increase of the split ratio into the PPP. In contrast, concentrations of alanine, leucine, and valine were increased with an increase of the split ratio into glycolysis. These results could provide a new engineering target for improving the production of the amino acids and the derivatives.

中文翻译：

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谷氨酸棒杆菌中糖酵解和磷酸戊糖磷酸途径之间的碳通量最佳比率，用于氨基酸积累。

葡萄糖通过诸如糖酵解和戊糖磷酸途径（PPP）等主要代谢途径代谢，以合成包括氨基酸在内的下游代谢产物。然而，糖酵解和PPP之间的碳通量分配比如何具体影响下游代谢产物的形成，目前尚不清楚。在这里，我们进行了全面的代谢组学分析，以研究糖酵解和PPP之间的分配比例对谷氨酸棒杆菌中氨基酸及其衍生物的细胞内浓度的影响。通过交换编码6-磷酸葡萄糖异构酶（PGI）的基因的启动子来改变分裂比。该比例与pgi相关转录水平和酶活性。苏氨酸和赖氨酸衍生物1，5-二氨基戊烷的浓度随PPP分配比的增加而增加。相反，丙氨酸，亮氨酸和缬氨酸的浓度随着糖酵解中的分配比的增加而增加。这些结果可为提高氨基酸及其衍生物的产量提供新的工程目标。