文章基本信息

标题：Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayers
本地全文：下载
作者：Kellen Brunaldi ; Manoel Arcisio Miranda ; Fernando Abdulkader 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2005
卷号：46
期号：02
页码：245-251
DOI：10.1194/jlr.M400155-JLR200
出版社：American Society for Biochemistry and Molecular Biology
摘要：The effect of palmitic acid (PA) and oleic acid (OA) on electrical parameters of planar membranes was studied. We found a substantial difference between the effects of PA and OA on proton transfer. PA induced a small increase in conductance, requiring a new technique for estimating proton-mediated currents across low-conductance planar bilayers in which an electrometer is used to measure the transmembrane current under virtual short circuit (SCC). Open-circuit voltage and SCC were used to determine proton and leak conductances. OA caused a marked increase in membrane conductance, allowing the use of a voltage-clamp technique. From SCC data, we were able to estimate the flip-flop rate constants for palmitate (1 x 10–6 s–1) and oleate (49 x 10–6 s–1) anions. Cholesterol, included in the membrane-forming solution, decreased importantly the leak conductance both in membranes unmodified by FA and in membranes modified by PA added to the bath.
关键词：lipid membranes • cholesterol • electrometer