Transmembrane movements of artificial redox mediators in relation to electron transport and ionic currents in chloroplasts.

Autor:	Bulychev, Alexander A., van Voorthuysen, Tijmen, Vredenberg, Wim J.
Předmět:	PLANT membranes CELL membranes OXIDATION-reduction reaction ELECTRONS CHLOROPLASTS PLASTIDS
Zdroj:	Physiologia Plantarum; Nov96, Vol. 98 Issue 3, p605-611, 7p
Abstrakt:	Electrochemical data obtained with TMPD+-sensitive electrodes indicate that ammonium-uncoupled chloroplasts retain TMPD (N,N,N′,N′-tetramethyl-p-phenylenediamine) mainly in the reduced form during illumination, whereas uncoupled DCMU-treated chloroplasts accumulate TMPD in the oxidized form (TMPD+). This observation indicates that the reduced plastoquinol is the preferred electron donor for photosystem I (PSI) and TMPD can only compete efficiently when plastoquinone reduction is blocked. After adding DCMU the formation of a transmembrane gradient for TMPD+ is reflected by a slow-down of the electrogenic electron transport and by the emerging of the overshoot of the membrane current in the light-off response. A light-dependent increase in photoelectric current generated by chloroplasts in the presence of NH4Cl and TMPD is observed and considered to be caused by a reversible release of current limitation in the interfacial conductance barriers in the lumen. [ABSTRACT FROM AUTHOR]
Databáze:	Complementary Index
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