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A threshold membrane potential accounts for controversial effects of fatty acids on mitochondrial oxidative phosphorylation
Author(s) -
Köhnke Detlef,
Ludwig Bernd,
Kadenbach Bernhard
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81616-8
Subject(s) - oxidative phosphorylation , uncoupling agents , biochemistry , mitochondrion , fatty acid , chemistry , inner mitochondrial membrane , thermogenesis , cytochrome c oxidase , phosphorylation , chemiosmosis , membrane potential , uncoupling protein , biology , biophysics , atp synthase , enzyme , adipose tissue , brown adipose tissue
The uncoupling effect of free fatty acids on oxidative phosphorylation in mitochondria has been known for more than 35 years. The mechanism of action, however, remains controversial. In this report the physicochemical basis of uncoupling was elucidated by studying the effect of free fatty acids on the proton permeability and membrane potential of proteoliposomes containing reconstituted cytochrome c oxidase (COX). A threshold membrane potential of about 125 mV was identified for fatty acid‐induced proton permeability. Only above this potential do free fatty acids translocate protons across the biological membrane. The data explain the controversial effects of long‐chain fatty acids on oxidative phosphorylation as well as their role on non‐shivering thermogenesis in larger mammals.