Lemeshko Victor V
Escuela de Física, Facultad de Ciencias, Universidad Nacional de Colombia, Calle 65, Cra. 64, Medellín AA3840, Colombia.
Eur Biophys J. 2006 Dec;36(1):57-66. doi: 10.1007/s00249-006-0101-7. Epub 2006 Oct 5.
A possibility of generation of the outer membrane potential in mitochondria has been suggested earlier in the literature, but the potential has not been directly measured yet. Even its nature, metabolic impact and a possible range of magnitudes are not clear, and require further theoretical and experimental analysis. Here, using simple mathematical model, we evaluated a possible contribution of the Donnan and metabolically derived potentials to the outer membrane potential, concluding that the superposition of both is most probable; exclusively Donnan origin of the potential is doubtful because unrealistically high concentrations of charged macromolecules are needed for maintaining its relatively high levels. Regardless of the mechanism(s) of generation, the maximal possible potential seems to be less than 30 mV because significant osmotic gradients, created at higher values, increase the probability of the outer membrane rupture. New experimental approaches for direct or indirect determination of true value of the outer membrane potential are suggested here to avoid a possible interference of the surface electrical potential of the inner membrane, which may change as a result of the extrusion of matrix protons under energization of mitochondria.
线粒体中外膜电位产生的可能性在早期文献中已有提及，但该电位尚未被直接测量。甚至其性质、代谢影响以及可能的幅度范围都不清楚，需要进一步的理论和实验分析。在此，我们使用简单的数学模型评估了唐南电位和代谢产生的电位对外膜电位的可能贡献，得出两者叠加最有可能的结论；仅由唐南电位产生这种情况值得怀疑，因为维持相对较高水平的电位需要高得不切实际的带电大分子浓度。无论产生机制如何，最大可能电位似乎小于30mV，因为更高值时产生的显著渗透梯度会增加外膜破裂的可能性。本文提出了直接或间接测定外膜电位真实值的新实验方法，以避免内膜表面电位可能产生的干扰，内膜表面电位可能因线粒体供能时基质质子的外排而发生变化。
