ISSN:
1432-1017
Keywords:
Electrical noise
;
membranes
;
ion pumps
;
active transport
;
fluctuations
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract 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 S 1 of current noise as a function of frequency, f. The shape of S I(f) contains information on the rate constants as well as on the magnitude of the charge displacements occuring during single reaction steps. The contribution of electrogenic pumps to the total voltage noise of the cell may be estimated from S I(f) and from the frequency-dependent impedance of the cell membrane.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00276627
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