[Thermodynamic characteristics of the interaction of high-potential cytochrome with dimer of bacteriochlorophyll in the reaction centers of Ectothiorhodospira shaposhnikovii chromatophores].
Kinetics of dark reduction of cytochrome CH (E7=290 mV) after its photoinduced oxidation chromatophores of E. shaposhnikovii at 110-210 K is analysed. A ratio is derived which describes dark reduction of cytochrome. This ratio makes it possible to determine the value of free energy of the electron transfer between cytochrome and bacteriochlorophyll dimer of the reaction centre (Bchl)2. The values of enthalpy and entropy of the transition under study at the temperatures below 210 K are equal to 1,67 kJ M-1 and 26,8 J M-1 K-1 correspondingly. A change of free energy obtained by linear extrapolation to the room temperature equals 9,71 kJ M-1. This value well agrees with the value 9,63 kJ M-1 obtained from the results of direct potentiometric titration of photoinduced redox transformations CH and (Bchl)2.
D020130:Bacterial Chromatophores / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001429:Bacteriochlorophylls / Q000378:metabolism*; D002734:Chlorophyll / Q000031:analogs & derivatives*; D002841:Chromatiaceae / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism*; D007700:Kinetics; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins
D001426:Bacterial Proteins; D001429:Bacteriochlorophylls; D003574:Cytochrome c Group; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D002734:Chlorophyll
Analiz termodinamicheskikh kharakteristik vzaimodeĭstviia vysokopotentsial'nogo tsitokhroma s dimerom bakteriokhlorofilla v reaktsionnykh tsentrakh khromatoforov Ectothiorhodospira shaposhnikovii.