ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES, cilt.49, ss.587-592, 1994 (SCI-Expanded)
The capability of different manganese complexes to act as PS II electron donors in D1/D2/cytochrome b559 complexes has been analyzed by measuring actinic light-induced absorption changes at 680 nm (650 nm) and 340 nm, reflecting the photoaccumulation of Pheophytin(-) (Pheo(-)) and the reduction of NADP(+), respectively. The data obtained reveal: a) the donor capacity of synthetic binuclear Mn(III)(2) complexes containing aromatic ligands significantly exceeds that for MnCl2 in both cases, i.e. Pheo(-) photoaccumulation and NADP(+) reduction; b) manganese complexes can serve as suitable electron donors for light-induced NADP(+) reduction catalyzed by D1/D2/cytochrome b559 complexes and ferredoxin plus ferredoxin-NADP(+) reductase under anaerobic conditions and c) the specific turnover rate of the system leading to NADP(+) reduction is extremely small.