Läuger P
Eur Biophys J. 1984;11(2):117-28. doi: 10.1007/BF00276627.
Active ion transport by ATP- or light-driven pumps involves a sequence of elementary steps such as binding and release of ions, as well as conformational transitions of the pump protein. At the microscopic level the individual reaction steps occur at random intervals, and therefore the current generated by electrogenic pumps fluctuates around a mean value. In this paper, a theoretical treatment of the electrical noise associated with active ion transport is given. The analysis, which is based on the calculation of the correlation function, yields the spectral intensity S1 of current noise as a function of frequency, f. The shape of S1(f) contains information on the rate constants as well as on the magnitude of the charge displacements occurring during single reaction steps. The contribution of electrogenic pumps to the total voltage noise of the cell may be estimated from S1(f) and from the frequency-dependent impedance of the cell membrane.
由ATP驱动或光驱动泵进行的主动离子运输涉及一系列基本步骤，如离子的结合与释放，以及泵蛋白的构象转变。在微观层面，各个反应步骤以随机间隔发生，因此由生电泵产生的电流围绕平均值波动。本文给出了与主动离子运输相关的电噪声的理论处理方法。该分析基于相关函数的计算，得出电流噪声的频谱强度S1作为频率f的函数。S1(f)的形状包含有关速率常数以及单个反应步骤中发生的电荷位移大小的信息。生电泵对细胞总电压噪声的贡献可根据S1(f)以及细胞膜的频率依赖性阻抗来估算。
