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Abstract

The aim of the work was to gain insight in the the mechanism of system 2. The primary and associated reactions of system 2 in active spinach chloroplasts were studied by means of submicrosecond emission spectroscopy of chlorophyll a. For the study of the primary acceptor of purple bacteria, which is analogous to that of system 2, in addition to the luminescence kinetics, the more specific absorption difference spectra were measured. In chloroplasts in which the plastoquinone acceptor is in the reduced state, Q-, below freezing point a laser induced 150 ns luminescence is observed, originating from system 2. This luminescence resulted from radical pair recombination. Since Q is in the reduced state before the laser flash, an electron acceptor, W**-, different from Q has to be postulated. The observation that the luminescence decay time is increased by a magnetic field is explained. The remarkable phenomenon that the 150 ns luminescence increases upon lowering the temperature from 200 to 50 K, is explained. Upon excitation of chromatophores of the purple bacterium Rhodospirillum rubrum with a 30 ps laser flash, bacteriochlorophyll luminescence was observed. This luminescence was caused by recombination of a radical pair. The absorption difference spectrum at 5 ns after the flash was determined.

Additional information

Authors: DUYSENS L N M, DEPARTMENT OF BIOPHYSICS, HUYGENS LABORATORY OF THE STATE UNIVERSITY, LEIDEN (THE NETHERLANDS);VAN BOCHOVE A C, DEPARTMENT OF BIOPHYSICS, HUYGENS LABORATORY OF THE STATE UNIVERSITY, LEIDEN (THE NETHERLANDS);SONNEVELD A DEPARTMENT OF BIOPHYSICS, HUYGENS LABORATORY OF THE STATE UNIVERSITY, LEIDEN (THE NETHERLANDS), DEPARTMENT OF BIOPHYSICS, HUYGENS LABORATORY OF THE STATE UNIVERSITY, LEIDEN (THE NETHERLANDS)
Bibliographic Reference: EUR 9135 EN (1984) MF, 11 P., BFR 120, BLOW-UP COPY BFR 150, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989123079900 / Last updated on: 1987-01-01
Category: PUBLICATION
Available languages: en