Duroquinol as an electron donor for chloroplast electron transfer reactions.
Duroquinol (tetramethylhydroquinone) was found to function as an electron donor in chloroplasts. Non-cyclic electron transfer from duroquinol to electron acceptors such as oxygen proceeded at high rates, was insensitive to 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) but was sensitive to the plastoquinone antagonist 2,5-dibromo-3-methyl-6-isopropyl-1,4-benzoquinone (DBMIB). The electron transport from duroquinol was coupled to the synthesis of ATP. Spectroscopic studies of chloroplast electron carriers in the dark indicated the high-potential "Rieske" iron-sulfur center, cytochrome f, plastocyanin and P-700 were all reduced by duroquinol. The dark reduction of the "Rieske" iron-sulfur center and cytochrome f were inhibited by DBMIB but not by DCMU. These results have been interpreted in terms of a linear sequence of electron carriers in the non-cyclic electron transport chain which includes plastoquinone, the "Rieske" iron-sulfur center, cytochrome f, plastocyanin and P-700.
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D002736:Chloroplasts / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism; D004237:Diuron / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D006873:Hydroquinones / Q000494:pharmacology*; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D010944:Plants; D010970:Plastocyanin / Q000378:metabolism; D010971:Plastoquinone / Q000378:metabolism
D003580:Cytochromes; D006873:Hydroquinones; D007506:Iron-Sulfur Proteins; D000255:Adenosine Triphosphate; D010970:Plastocyanin; D004237:Diuron; D010971:Plastoquinone; C016421:duroquinol