Photoreduction of silicomolybdate in chloroplasts by agents accelerating the deactivation reactions of the water-oxidizing system.
Uncouplers of photosynthetic phosphorylation, CCCP, TTFB and PCP, inhibited light-induced O2 evolution in the Hill reaction with SiMo (I50 approximately 20, 3 and 45 microM, respectively), but only insignificantly diminished SiMo photoreduction by pea chloroplasts. The same properties were exhibited by the ADRY agent ANT2p. CCCP, TTFB and PCP are oxidizable compounds with redox potentials of +1.17, +1.18 and +1.09 V (pH 6.0), as determined by cyclic voltammetry. Similarly to NH2OH, the tested uncouplers can apparently serve as electron donors for photosystem II.
Samuilov
V D
VD
Department of Cell Physiology and Immunology, Moscow State University, Russian Federation.
Barsky
E L
EL
Gubanova
O N
ON
Klimov
V V
VV
Kozlov
Y N
YN
D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D004579:Electron Transport; D066298:In Vitro Techniques; D008982:Molybdenum / Q000378:metabolism*; D010084:Oxidation-Reduction; D018532:Pisum sativum; D010777:Photochemistry; D045322:Photosynthetic Reaction Center Complex Proteins / Q000187:drug effects / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D017655:Silicon Compounds / Q000378:metabolism*; D014475:Uncoupling Agents / Q000494:pharmacology*; D014867:Water / Q000378:metabolism*
D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D017655:Silicon Compounds; D014475:Uncoupling Agents; D014867:Water; C013250:silicomolybdate; D008982:Molybdenum