Short-Term Metabolome Dynamics and Carbon, Electron, and ATP Balances in Chemostat-Grown Saccharomyces cerevisiae CEN.PK 113-7D following a Glucose Pulse
Short-Term Metabolome Dynamics and Carbon, Electron, and ATP Balances in Chemostat-Grown Saccharomyces cerevisiae CEN.PK 113-7D following a Glucose Pulse
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DOI：
10.1128/aem.72.5.3566-3577.2006
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发表时间：
2006-05
影响因子：
4.4
通讯作者：
Liang Wu;J. V. van Dam;D. Schipper;M. Kresnowati;Angela M. Proell;C. Ras;W. V. van Winden;W. V. van Gulik;J. Heijnen
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文献类型：
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作者：
Liang Wu;J. V. van Dam;D. Schipper;M. Kresnowati;Angela M. Proell;C. Ras;W. V. van Winden;W. V. van Gulik;J. Heijnen
摘要：在需氧、碳限制的恒化培养物中施加葡萄糖脉冲后，在 300 秒的短暂时间内评估了酿酒酵母 CEN.PK 113-7D 的体内动力学。我们量化了细胞外代谢物、初级代谢中细胞内中间产物、细胞内游离氨基酸以及体内 O2 摄取和 CO2 释放速率的反应。通过这些测量，建立了动态碳、电子和 ATP 平衡，以确定脉冲后时期的主要碳、电子和能量汇。在此期间存在三个不同的代谢阶段。在第一阶段（脉冲后 0 至 50 秒），碳/电子平衡接近 85%。糖酵解和储存化合物的积累占消耗葡萄糖的 60%，导致能量消耗，并可能导致合成代谢通量暂时减少。在第二阶段（50至150秒），发酵代谢逐渐成为最重要的碳/电子汇。在第三阶段（150至300秒），测量中未识别出29%的碳吸收，并且ATP平衡有大量盈余。这些结果表明合成代谢通量增加，这与细胞外通量的宏观平衡以及观察到的与非发酵代谢相关的二氧化碳释放增加一致。在基于短期动态代谢组反应的体内动力学模型中，必须考虑到涉及主要碳、电子和能量汇的已确定的代谢过程。
ABSTRACT The in vivo kinetics in Saccharomyces cerevisiae CEN.PK 113-7D was evaluated during a 300-second transient period after applying a glucose pulse to an aerobic, carbon-limited chemostat culture. We quantified the responses of extracellular metabolites, intracellular intermediates in primary metabolism, intracellular free amino acids, and in vivo rates of O2 uptake and CO2 evolution. With these measurements, dynamic carbon, electron, and ATP balances were set up to identify major carbon, electron, and energy sinks during the postpulse period. There were three distinct metabolic phases during this time. In phase I (0 to 50 seconds after the pulse), the carbon/electron balances closed up to 85%. The accumulation of glycolytic and storage compounds accounted for 60% of the consumed glucose, caused an energy depletion, and may have led to a temporary decrease in the anabolic flux. In phase II (50 to 150 seconds), the fermentative metabolism gradually became the most important carbon/electron sink. In phase III (150 to 300 seconds), 29% of the carbon uptake was not identified in the measurements, and the ATP balance had a large surplus. These results indicate an increase in the anabolic flux, which is consistent with macroscopic balances of extracellular fluxes and the observed increase in CO2 evolution associated with nonfermentative metabolism. The identified metabolic processes involving major carbon, electron, and energy sinks must be taken into account in in vivo kinetic models based on short-term dynamic metabolome responses.