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The permeability of the thylakoid membrane for protons
Author(s) -
Schönfeld Mordechay,
Schickler Hedva
Publication year - 1984
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(84)80132-5
Subject(s) - thylakoid , proton , electrochemical gradient , leakage (economics) , proton transport , electron transport chain , chloroplast , membrane , chemistry , permeability (electromagnetism) , biophysics , chemiosmosis , proton pump , analytical chemistry (journal) , atpase , chromatography , biochemistry , biology , physics , atp synthase , nuclear physics , macroeconomics , economics , gene , enzyme
Parallel measurements of light‐induced proton gradients and of electron transport rates were used to characterize proton efflux in lettuce chloroplasts. Proton efflux mediated by the chloroplast H + ‐ATPase was resolved from nonspecific leakage, through its dependence on the ratio of internal to external proton concentrations; proton leakage was proportional to the difference between these two concentrations. The proton permeability of the thylakoid membrane was found in these experiments to be 2 × 10 −5 cm/s. In spite of this rather high permeability, proton leakage accounted for only ~1% of the total proton flux, due to the low internal proton concentration.