Light Dependent Reduction of Pertechnetate (TcO(4)) by Broken Chloroplasts.

Arguments are given for a ferredoxin-mediated reduction of TcO(4) (-), preponderantly into extractable Tc(V) complexes, by illuminated, broken chloroplasts. Photosynthetic O(2)- and NADP-reduction competitively inhibit Tc incorporation. As for O(2), the reaction can be stimulated by the auto-oxidizable electron acceptor methyl viologen. Furthermore TcO(4) (-) can function as terminal acceptor in the diaphorase reaction, with NADPH as electron donor.