Proton mobility in biological membranes: the relationship between membrane lipid state and proton conductivity

FEBS Letters

O'Shea, Paul S.¹  Azzi, Angelo¹  Petrone, Goffredo¹  Thelen, Sylvia¹ 

[1] Medizinisch-Chemisches Institut, Universität Bern, Bern, Postfach-3000, Switzerland

关键词: Proton conductivity Lipid microviscosity Order parameter Membrane fluidity Permeability coefficient Fluorescence polarisation;   

DOI  :  10.1016/0014-5793(84)80883-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

It is demonstrated that phospholipid vesicles and mitochondria are relatively permeable to ionised water with a permeability coefficient of approx. 10⁻⁴–10⁻³ . The H⁺/OH⁻ conductance is further shown to depend in a non-linear fashion upon an applied electric field and in a linear fashion upon applied pH gradients. In an attempt to characterise the molecular basis of these phenomena, the effects of electric fields of various magnitudes upon the relative dynamic state of the membrane were studied using the technique of fluorescence polarisation. It was found that the steady-state fluorescence polarisation of 1,6-diphenyl-1,3,5-hexatriene (DPH) was dependent upon the applied field in a similar manner to the proton conductance. Whereas the effect of a thermodynamically equivalent pH gradient had a negligible effect. There was thus a correlation between the “state” of the membrane and the rate of permeation of H⁺/OH⁻.

【 授权许可】

Unknown