Does diphenylene iodonium chloride have any effect on the O2- -generating step of plant peroxidases?
The O2*- -generating step of plant peroxidases during their catalytic cycle is represented by the decay of compound III (CoIII) into ferriperoxidase, which most likely involves the dissociation of a ferric-O2*- complex to yield the ferric form of the enzyme and O2*-. Diphenylene iodonium chloride (DPI), at 50-100 microM, does not significantly enhance the stability of CoIII of peroxidase, as judged by the values of k(decay), and therefore, DPI appears to have no effect on the O2*- -generating step of plant peroxidases. From these results, it is concluded that caution should be exercised when considering peroxidase as a possible enzyme target of O2*- -mediated plant physiological processes sensitive to DPI inhibition.
Barceló
A R
AR
Department of Plant Biology (Plant Physiology), University of Murcia, Spain.
Ferrer
M A
MA
D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability / Q000187:drug effects; D006735:Horseradish Peroxidase / Q000378:metabolism*; D007700:Kinetics; D009861:Onium Compounds / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D013053:Spectrophotometry
D009861:Onium Compounds; D010940:Plant Proteins; C007517:diphenyleneiodonium; D006735:Horseradish Peroxidase; D010100:Oxygen