无氧微生物的新陈代谢可以接近热力学极限
Bradley E Jackson1, Michael J McInerney
1Department of Botany and Microbiology, University of Oklahoma, Norman 73019-2045, USA.
Nature
|January 25, 2002
概括
合成细菌可以在热力学平衡附近代谢基质,挑战最小能量保存概念. 这表明高效的细菌代谢系统运行在最小的自由能量.
科学领域:
- 微生物学 微生物学
- 生物化学 生物化学
- 热力学是一种热力学.
背景情况:
- 发酵细菌使用低自由能变化 (DeltaG') 的反应来生长,通过转移将新陈代谢与ATP合成合起来.
- 一个普遍的概念表明,生物系统以离散的数量保存能量,最小可转换值为-20 kJ mol-1,阻止无氧基质衰变.
- 这个最小能量值预测代谢在达到热力学平衡 (DeltaG' ≈ 0 kJ mol-1) 之前就会停止.
研究的目的:
- 研究微生物新陈代谢在合成协会中的能量极限.
- 为了确定合成细菌是否可以在热力学平衡或接近热力学平衡时运行.
- 探索影响微生物群落中基质代谢停止的自由能量因素.
主要方法:
- 研究微生物的新陈代谢在合成协会,其中一个物种的降解取决于另一个的最终产品的去除.
- 在这些协会中分析了基质代谢期间自由能量 (DeltaG') 的变化.
- 研究了终端电子接受反应,基质激活能量和剩余的自由能量之间的关系.
主要成果:
- 综合性关联被证明可以在接近热力学平衡的自由能量值 (DeltaG' ≈ 0 kJ mol-1) 上代谢基质.
- 代谢停止的自由能量不是一个恒定的最小值,而是有所变化.
- 接近平衡的新陈代谢受到特定终端电子接受反应和基质激活能量需求的影响.
结论:
- 生物能量保存的固定最小自由能量概念受到合成代谢的挑战.
- 合成协会表明,细菌可以在热力学平衡附近运行极其高效的代谢系统.
- 微生物群落可以在接近热力学平衡的条件下实现高效的能量收获.
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