Abstract
The properties of the ferredoxin-catalysed cyclic photophosphorylation in lyophilised and lysozyme treated Anacystis nidulans with rates up to 80 μmoles ATP/h/mg chlorophyll are described. The concentration of ferredoxin needed for the saturation of the ferredoxin-catalysed cyclic photophosphorylation is about 6 — 8 times higher than for NADP-reduction. In contrast to the ferredoxin-catalysed cyclic photophosphorylation in spinach chloroplasts the reaction in Anacystis is relatively intensive to the “poising“ of the system and is not affected by antimycin A. Whilst under aerobic conditions in broken chloroplasts ferredoxin catalyses a pseudocyclic photophosphorylation in which H2O2 is a component, in Anacystis on addition of ferredoxin ATP is only formed on the cyclic pathway even in air. In chloroplasts as well as in Anacystis disulfo-disalicylidenpropandiamin (DSPD) inhibits only the ferredoxin-catalysed cyclic photophosphorylations and the NADP-reductions, but not the ferredoxin stimulated ATP-formations under aerobic conditions. Evidence is presented once more that ferredoxin is the cofactor of cyclic photophosphorylation in vivo.

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