An EPR spin-probe and spin-trap study of the free radicals produced by plant plasma membranes

Abstract

Plant plasma membranes are known to produce superoxide radicals, while the production of hydroxyl radical is thought to occur only in the cell wall. In this work it was demonstrated using combined spin-trap and spin-probe EPR spectroscopic techniques, that plant plasma membranes do produce superoxide and hydroxyl radicals but by kinetically different mechanisms. The results show that superoxide and hydroxyl radicals can be detected by DMPO spin-trap and that the mechanisms and location of their production can be differentiated using the reduction of spin-probes Tempone and 7-DS. It was shown that the mechanism of production of oxygen reactive species is NADH dependent and diphenylene iodonium inhibited. The kinetics of the reduction of Tempone, combined with scavengers or the absence of NADH indicates that hydroxyl radicals are produced by a mechanism independent of that of superoxide production. It was shown that a combination of the spin-probe and spin-trap technique can be used in free radical studies of biological systems, with a number of advantages inherent to them.

[Fe(CN)5(isoniazid)]3−: An iron isoniazid complex with redox behavior implicated in tuberculosis therapy

“…(Table 1, SupportingFigure S10)[32,50]. However, peroxyacylpyridine species could emerge as well from isoniazid oxidation as described before, which bound to a metal moiety could lead to such radical trapped.…”

Oxidative Stability of Lipids by Means of EPR Spectroscopy and Chemiluminescence

“…lipid radicals) [13][14][15][16], whereas DMPO [5,5-dimethyl-1-pyrroline-Noxide] is useful for trapping such radicals as OHÁ, CH 3 Á, and O ÁÀ 2 . The latter trap is much less radical-specific and significantly less stable after trapping a radical [13][14][15][16][17][18][19][20][21]. The POBN trap is not as commonly used as DMPO.…”

EPR spectroscopy and its use in planta—a promising technique to disentangle the origin of specific ROS

“…Spin traps are stable, diamagnetic compounds that form longerlived radical species with transient, very reactive radicals with low half-lives of only 10 −9 to 10 −1 s. The paramagnetic spin adducts are stable for minutes or even hours, accumulate in the tissue and reach a sufficient concentration for detection by EPR (Mojovié et al, 2005). The prerequisites for suitable spin traps are defined by their ability either to exclusively trap one radical species or to lead to different specific signature EPR spectra.…”