Some properties of the H2O2/O2- generating system from the lignifying xylem of Zinnia elegans.
The properties of the enzymatic system responsible for generating H2O2/O2- in the lignifying xylem of Zinnia elegans were studied using the starch/KI method for monitoring H2O2 production and the nitroblue tetrazolium method for monitoring superoxide anion production. The results showed that H2O2/O2- production by lignifying xylem tissues was insensitive to inhibitors of peroxidase and poly(di)amine oxidases. However, H2O2/O2 production in the xylem of Z. elegans was sensitive to the inhibitors of phagocytic plasma membrane NADPH oxidase, pyridine, imidazole, quinacrine and diphenylene iodonium. The sensitivity of H2O2/O2- production to the respective inhibitors of calmodulin (R-24571), phospholipase C (neomycin sulfate), and protein kinase (staurosporine), and its reversion by an inhibitor of protein phosphatases (cantharidin); pointed to the analogies existing between the mechanism of H2O2/O2- production in the lignifying xylem of Z. elegans and the oxidative burst observed during the hypersensitive plant cell response. These results suggest the existence of a metabolic cascade involving calmodulin, IP3 and protein phosphorylation in the activation of the enzymatic system responsible for H2O2/O2- production in the lignifying xylem of Z. elegans.
Barceló
A R
AR
Department of Plant Biology (Plant Physiology), University of Murcia, Spain.
D019659:Asteraceae / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008031:Lignin / Q000378:metabolism*; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000037:antagonists & inhibitors / Q000378:metabolism; D010544:Peroxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D000097667:Polyamine Oxidase
D002147:Calmodulin; D002374:Catalase; D004791:Enzyme Inhibitors; D006861:Hydrogen Peroxide; D015544:Inositol 1,4,5-Trisphosphate; D008031:Lignin; D019255:NADPH Oxidases; D000587:Oxidoreductases Acting on CH-NH Group Donors; D010544:Peroxidases; D011494:Protein Kinases; D013482:Superoxide Dismutase; D013481:Superoxides; D000097667:Polyamine Oxidase