caa a22 4500 397520999 CHVBK 20180308164632.0 cr unu---uuuuu 161202e199511 xx s 000 0 eng 10.1093/jxb/46.11.1677 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.11.1677 Possible interaction between peroxidase and NAD(P)H-dependent nitrate reductase activities of plasma membranes of corn roots [Elektronische Daten] [Ario de Marco, Roberto Pinton, Elke Fischer-Schliebs, Zeno Varanini] The relationship between the plasma membrane bound NAD(P)H-nitrate reductase (NR) and a plasma membrane (PM)-bound peroxidase was investigated using highly purified PM vesicles isolated from corn roots. The PM-bound NR activity was strongly enhanced by MnCl2 and SHAM, which stimulated peroxidase activity. Since both activities, the NAD(P)H-dependent NR and the peroxidase compete for NAD(P)H as electron donor, we propose a model in which a product of peroxidation is able to offer electrons to the nitrate reductase in a more reactive form with respect toNAD(P)H. Our hypothesis was confirmed by experiments in which the effects of inhibitors of peroxidative reactions, catalase, superoxide dismutase, and ascorbate on the PM-bound NR were studied. Results indicate that the putative electron donor for nitrate reduction could be a radicalic species, possibly NAD. Furthermore, since cytochrome c decreased the activity of the plasma membrane-bound NAD(P)Hdependent NR, cytochrome b557 might be the site of the enzyme accepting electrons from NAD. Our results indicate that the PM environment of the NR may be involved in the extent of the membrane associated nitrate reduction and that redox enzymes at the PM, the NAD(P)H-NR and a peroxidase-like NADH-oxidase, can interact. © Oxford University Press RESEARCH PAPERS nationallicence Plasma membrane-bound nitrate reductase nationallicence peroxidase nationallicence Zea mays nationallicence Marco Ario de Dipartimento di Produzione Vegetale e Tecnologie Agrarie, Universita di Udine via delle Scienze 208, 1-33100 Udine, Ital aut Pinton Roberto Dipartimento di Produzione Vegetale e Tecnologie Agrarie, Universita di Udine via delle Scienze 208, 1-33100 Udine, Ital aut Fischer-Schliebs Elke Institut für Botanik, Technische Hochschule Darmstadt Schnittspahnstrasse 3-5, D-64287 Darmstadt, FRG aut Varanini Zeno Dipartimento di Produzione Vegetale e Tecnologie Agrarie, Universita di Udine via delle Scienze 208, 1-33100 Udine, Ital aut Journal of Experimental Botany Oxford University Press 46/11(1995-11), 1677-1683 0022-0957 46:11<1677 1995 46 exbotj https://doi.org/10.1093/jxb/46.11.1677 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.11.1677 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Marco Ario de Dipartimento di Produzione Vegetale e Tecnologie Agrarie, Universita di Udine via delle Scienze 208, 1-33100 Udine, Ital aut NATIONALLICENCE 700 1- Pinton Roberto Dipartimento di Produzione Vegetale e Tecnologie Agrarie, Universita di Udine via delle Scienze 208, 1-33100 Udine, Ital aut NATIONALLICENCE 700 1- Fischer-Schliebs Elke Institut für Botanik, Technische Hochschule Darmstadt Schnittspahnstrasse 3-5, D-64287 Darmstadt, FRG aut NATIONALLICENCE 700 1- Varanini Zeno Dipartimento di Produzione Vegetale e Tecnologie Agrarie, Universita di Udine via delle Scienze 208, 1-33100 Udine, Ital aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/11(1995-11), 1677-1683 0022-0957 46:11<1677 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford