Interpreting ion fluxes to channel arrays in monolayers.
The exponentially decaying permeability model interprets the chronoamperometric currents arising from Tl+ reduction at a Hg electrode covered with a phospholipid monolayer (DOPC) containing gramicidin monomer by combining three processes: (i) the diffusion of an ion to a membrane surface with an array of channels, (ii) the conformational dynamics of the individual channels, and (iii) the passage of the ion through the channels. The introduction of a variable permeability allows us to uncouple the diffusion from the heterogeneous processes, given that the concentration of a species at the active surface can be obtained by semi-integration of the currents. Consideration of a reverse step for the dehydration process at the mouth of the channel allows the analysis of potential steps away from diffusion-limited conditions where a Nernstian-like behavior of the relevant parameter is observed. The model has been successfully applied to data with all trans retinol or benzo-alpha-pyrene as additive to the phospholipid monolayer and to monolayers without any additive at all.
Monné
Josep
J
Departament de Química, Universitat de Lleida, Rovira Roure 191, 25198 Lleida, Spain.
Díez
Yolanda
Y
Puy
Jaume
J
Galceran
Josep
J
Nelson
Andrew
A
D001564:Benzo(a)pyrene / Q000737:chemistry; D004566:Electrodes; D007473:Ion Channels / Q000737:chemistry*; D008628:Mercury / Q000737:chemistry; D012172:Retinaldehyde / Q000737:chemistry
D007473:Ion Channels; D001564:Benzo(a)pyrene; D008628:Mercury; D012172:Retinaldehyde