[Effect of copper ions on the light-induced proton transfer in spinach chloroplasts].
It was shown that the light-dependent proton uptake by a suspension of isolated chloroplasts was completely inhibited in the presence of 30-50 microM Cu2+ ions at the 0.1-0.3 Cu2+/Chl ratio. At the same time, the rate of photosynthetic oxygen evolution in the presence of 30-200 microM CuSO4 was reduced by no more than 20-30% of control and up to 50% of the control DeltapH value was retained. The results allow us to suppose that, in the presence of copper ions: 1) electron transport in PS2 is inhibited at the level of the secondary quinone acceptor Q(B) whose photoreduction is accompanied by proton uptake from external medium; and 2) an alternative pathway of electron transfer to terminal acceptor is activated, which provides the photooxidation of water and the formation of transmembrane proton gradient.
Podorvanov
V V
VV
Polishchuk
A V
AV
Zolotareva
E K
EK
D000643:Ammonium Chloride / Q000494:pharmacology; D001692:Biological Transport; D002413:Cations, Divalent; D002736:Chloroplasts / Q000187:drug effects* / Q000378:metabolism; D003300:Copper / Q000494:pharmacology*; D004579:Electron Transport; D006096:Gramicidin / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008027:Light; D010100:Oxygen / Q000502:physiology; D010788:Photosynthesis; D011522:Protons; D018724:Spinacia oleracea / Q000378:metabolism*
D002413:Cations, Divalent; D011522:Protons; D000643:Ammonium Chloride; D006096:Gramicidin; D003300:Copper; D010100:Oxygen