Abstract
Various mono-and diazaphenanthrenes were prepared and assayed for their activity as inhibitors of photosynthetic electron flow in isolated chloroplasts in order to get more insight into the mechanism of action of the well known inhibitor o-phenanthroline = 1,10-diazaphenanthrene. The results show that 1-, 4-and 5-azaphenanthrene are only slightly less active than 1,10-diazaphen-anthrene. In the case of the different diazaphenanthrenes, 1,4-, 1,7-and 5,6-diazaphenanthrene exhibited somewhat lower activity than 1,10-diaphenanthrene, whereas 2,9-and 4,7-diazaphen-anthrene were completely inactive. Substitution at C-atoms of 1,10-diazaphenanthrene leads to an increase in activity in the case of the 4-and 7-position, regardless of electropositive or electro negative substituents, whereas substitution at the 2-, 3-, 5-, 6-, 8-and 9-position leads to a de creased activity. The ability of 1,10-diazaphenanthrene to form iron complexes seems to be of little relevance to the inhibitory activity on photosynthetic electron transport. This follows also from the fact that other strong iron complexing agens, like 2.2'-bipyridine or 8-hydroxyquinoline, are not inhibitory
Photo-induced electron transfer in intact cells of Rubrivivax gelatinosus mutants deleted in the RC-bound tetraheme cytochrome: Insight into evolution of photosynthetic electron transport
