RT Journal Article
SR Electronic
T1 The Superoxide Synthases of Plasma Membrane Preparations from Cultured Rose Cells
JF Plant Physiology
JO Plant Physiol.
FD American Society of Plant Biologists
SP 621
OP 629
DO 10.1104/pp.110.2.621
VO 110
IS 2
A1 Murphy, T. M.
A1 Auh, C. K.
YR 1996
UL http://www.plantphysiol.org/content/110/2/621.abstract
AB Preparations of plasma membranes isolated from cultured rose (Rosa damascena Mill. cv Gloire de Guilan) cells synthesized O2- when incubated with either NADH or NADPH, as measured by an O2--specific assay based on the chemiluminescence of lucigenin. The activities were strongly dependent on the presence of Triton X-100. The Km for NADH was 159 [mu]M; that for NADPH was 19 [mu]M. Neither NADH- nor NADPH-dependent activity was inhibited by azide, an inhibitor of peroxidase, nor by antimycin A, an inhibitor of mitochondrial electron transport; both activities were inhibited by 30 to 100 nM diphenylene iodonium, an inhibitor of the mammalian NADPH oxidase. The NADH- and NADPH-dependent activities could be distinguished by detergent solubilization and ultracentrifugation: the NADH-dependent activity sedimented more easily, whereas the NADPH-dependent activity remained in suspension. One or both of these enzymes may provide the O2- seen when plant cells are exposed to pathogens or pathogen-associated elicitors; however, plasma membranes from rose cells treated with a Phytophthora elicitor had the same activity as control cells.