Title: Sites of cytochrome <i>b</i>‐563 reduction, and the mode of action of DNP‐INT and DBMIB in the chloroplast cytochrome <i>b</i>‐563/<i>f</i> complex
Abstract:When ferredoxin is the reductant of cytochrome b ‐563 in the chloroplast cytochrome b ‐563/ f complex, the reaction rate varies with pH in a manner which permits identification of a plastoquinone/plas...When ferredoxin is the reductant of cytochrome b ‐563 in the chloroplast cytochrome b ‐563/ f complex, the reaction rate varies with pH in a manner which permits identification of a plastoquinone/plastosemiquinone couple as an intermediate in the reaction. The requirement for the inhibitor, DNP‐INT, in this reaction, suggests that there are two sites in the complex where plastosemiquinone can react with cytochrome(s) b ‐563. The ineffectiveness of DBMIB in promotion of ferredoxin‐mediated cytochrome b ‐563 reduction has led to a model where DBMIB and DNP‐INT inhibit different electron transfer steps at the same, or overlapping, sites in the complex.Read More