Post-illumination kinetics of cytochrome f reduction in chloroplast thylakoid in the presence of dibromothymoquinone.
Addition of dibromothymoquinone (DBMIB) to isolated chloroplast thylakoids reduces cytochrome f in the dark. Reduced cytochrome f is oxidised when the thylakoids are illuminated, and is re-reduced in the subsequent darkness. The rate of re-reduction in the dark is faster after red (650 nm) illumination than after far red (713 nm) illumination. In the presence of DCMU or upon heat treatment or at high (greater than 10 microM) concentration of DBMIB the rate of dark reduction after red illumination becomes slower and equal to that after far red illumination, suggesting that photosystem II electron transfer at least upto plastoquinone facilitates DBMIB-mediated reduction of cytochrome f in the thylakoids.
D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism*; D045348:Cytochromes f; D003624:Darkness; D003991:Dibromothymoquinone / Q000494:pharmacology*; D006873:Hydroquinones / Q000494:pharmacology; D007700:Kinetics; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000187:drug effects; D011809:Quinones / Q000494:pharmacology*
D003580:Cytochromes; D006873:Hydroquinones; D011809:Quinones; D003991:Dibromothymoquinone; D045348:Cytochromes f