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Modes of action of uncouplers in thylakoids
Author(s) -
Schönfeld Mordechay,
Schickler Hedva
Publication year - 1989
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(89)80133-4
Subject(s) - thylakoid , electron transport chain , chloroplast , biophysics , chemistry , membrane , chemical physics , biochemistry , biology , gene
The pH dependence of electron transport in isolated lettuce chloroplasts can be simulated by a model involving four ionizable groups: two facing the inside and two facing the outside of the thylakoids. The pH dependence can be resolved into separate pH profiles for the outside and the inside of the thylakoids, with optima at 7.1 and 5.6, respectively. A ΔpH of 3 units across the thylakoid membrane allows only partial overlapping of the two profiles and relatively low rates of electron transport. Uncouplers stimulate electron transport by reducing the ΔApH, thereby improving the overlapping of the two pH profiles.