Hockings P D, Rogers P J
Division of Science and Technology, Griffith University, Nathan, Australia.
Eur J Biochem. 1997 Jun 1;246(2):574-9. doi: 10.1111/j.1432-1033.1997.00574.x.
The theory that some bacteria can save energy by an energy-recycling process, in which protons are excreted with metabolic end-products with variable stoichiometry, has been examined by 1H-NMR. A method has been developed that utilises observed differences in the Hahn T2 relaxation of metabolites in the intracellular and extracellular compartments to distinguish and quantify metabolite signals originating from both compartments. It was found that the lactate electrochemical-potential gradient calculated from the fraction of lactate that is sufficiently mobile to contribute to the NMR signal was in exact balance with the proton electrochemical-potential gradient over a wide range of pH values. The conclusion was reached that previous reports of variable stoichiometry were due to 'bound' lactate at high intracellular pH that could neither contribute neither to the NMR signal nor to the lactate electrochemical-potential gradient.
某些细菌可通过能量循环过程节省能量的理论已通过1H-NMR进行了研究，在该能量循环过程中，质子与代谢终产物以可变化学计量排出。已开发出一种方法，该方法利用细胞内和细胞外区室中代谢物的哈恩T2弛豫的观察差异来区分和量化源自两个区室的代谢物信号。结果发现，根据足以对NMR信号有贡献的可移动乳酸部分计算出的乳酸电化学势梯度，在很宽的pH值范围内与质子电化学势梯度精确平衡。得出的结论是，先前关于可变化学计量的报道是由于细胞内高pH值下的“结合”乳酸，其既不能对NMR信号也不能对乳酸电化学势梯度有贡献。
