Increase of local hydrogen ion gradient near bilayer lipid membrane under the conditions of catalysis of proton transfer across the interface

FEBS Letters

Antonenko, Yuri N¹  Yaguzhinsky, Lev S¹  Evtodienko, Veronika Yu¹ 

[1] A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia

关键词: Proton coupling;    Bilayer lipid membrane;    Unstirred layer;    Nigericin;    Buffer;    Proton exchange;    TTFB;    a protonophore;    tetrachlorotrifluoromethylbenzimidazole;    BLM;    bilayer lipid membrane;    USL;    unstirred layer near the BLM;   

DOI  :  10.1016/S0014-5793(98)00233-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The measurements of pH profiles in the unstirred layers (USLs) near planar bilayer lipid membranes (BLM) were applied for the evaluation of the hydrogen ion fluxes which were induced by nigericin in the presence of potassium ion gradients. It was shown that at high concentrations of KCl the increase in the concentration of citrate buffer caused an anomalous effect, namely, an increase in the local pH shifts in the USLs. The hydrogen ion flux rose 50 times upon the increase in the citrate concentration from 1 mM to 20 mM. Phosphate stimulated the flux 7 times under these conditions. In agreement with our previous results, at low KCl concentrations, when the process is limited by the K⁺-nigericin interaction, an increase in the buffer concentration led to a reduction of the local pH shifts, under these conditions the usual concentration dependence was observed. The data obtained favor the model implying the existence of the kinetic barrier for proton transfer at the membrane-water interface.

【 授权许可】

Unknown