Proton correlation nuclear magnetic resonance study of metabolic regulations and pyruvate transport in anaerobic Escherichia coli cells.
Proton correlation nuclear magnetic resonance study of metabolic regulations and pyruvate transport in anaerobic Escherichia coli cells.
复制标题
厌氧大肠杆菌细胞代谢调节和丙酮酸转运的质子相关核磁共振研究。
DOI：
10.1021/bi00557a008
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发表时间：
1980
期刊：
影响因子：
2.9
通讯作者：
S. Fujiwara
中科院分区：
文献类型：
--
作者：
T. Ogino;Y. Arata;S. Fujiwara
T. Ogino、*'* Y. Arata、* 和 S. Fujiwara 摘要：质子相关核磁共振 (NMR) 用于研究厌氧大肠杆菌细胞中葡萄糖代谢和丙酮酸转运的动力学方面。结果表明，在大肠杆菌细胞的无氧代谢中，即使葡萄糖供应充足，乳酸的量仍持续增加，而乙酸、乙醇、琥珀酸和甲酸的浓度则趋于平稳。使用葡萄糖-/-13C作为唯一碳源分别对通过Embden-Meyerhof途径和戊糖单磷酸途径的代谢进行定量。结论是多达 22% 的葡萄糖通过戊糖分流被分解代谢。即使在代谢率趋于平稳后，两条竞争途径的贡献比例也保持不变。结果表明，低 pH 值下糖酵解速率急剧降低。培养基pH值的降低也改变了发酵，使得产生的乙酸盐的量大约是乙醇的两倍，并且产生的乳酸盐比观察到的其他代谢物丰富得多。这些结果表明，在厌氧条件下，培养基的 pH 值是决定糖酵解速率和控制代谢途径的重要因素。当糖酵解被碘乙酸抑制时，外源乳酸被细胞吸收，并主要通过丙酮酸进一步代谢为乙酸，
T. Ogino,*'* Y. Arata,* and S. Fujiwara abstract: Proton correlation nuclear magnetic resonance (NMR) was used tostudy dynamical aspects of glucose me-tabolism and pyruvate transport in anaerobic Escherichia coli cells. It was shown that, in the anaerobic metabolism of E. coli cells, the amount of lactate continues to increase, whereas the concentrations of acetate, ethanol, succinate, and formate level off even when the supply of glucose is sufficient. Me-tabolisms via the Embden-Meyerhof pathway and the pentose monophosphate pathway were separately quantitated by using glucose-/-l3C as the sole carbon source. It was concluded that as much as 22% of the glucose is catabolized via the pentose shunt. The ratioof contributions from the two competing pathways remains unchanged even after the rates of metab-olism leveled off. It was shown that the rate of glycolysis is drastically reduced at low pH. The decrease in pH of the medium also shifted the fermentation insuch a way that the quantity of acetate produced is about twice that of ethanol and that lactate produced is much more abundant than other metabolites observed. These results indicate that under anaerobic conditions the pH of the medium is an important factor in determining therate of glycolysis and in controlling the metabolic pathways. When glycolysis is inhibited by iodoacetate, an exogenous lactate is taken up by the cell and further metabolized primarily to acetate through pyruvate,