Peroxynitrites metal salts

The metal salts of peroxynitrite have also been studied using ab initio methods. We use the same nomenclature as McGrath and Powland s early paper on ONO—OH , which distinguishes different conformers by their dihedral angles. For example, the structure with a cis ONO—O arrangement and the alkali atom bonded to the terminal oxygen with a perpendicular orientation is called cis,perp Figure 1 describes the conformational aspects of the conformers studied. 

Thus, the mechanism of MT antioxidant activity might be connected with the possible antioxidant effect of zinc. Zinc is a nontransition metal and therefore, its participation in redox processes is not really expected. The simplest mechanism of zinc antioxidant activity is the competition with transition metal ions capable of initiating free radical-mediated processes. For example, it has recently been shown [342] that zinc inhibited copper- and iron-initiated liposomal peroxidation but had no effect on peroxidative processes initiated by free radicals and peroxynitrite. These findings contradict the earlier results obtained by Coassin et al. [343] who found no inhibitory effects of zinc on microsomal lipid peroxidation in contrast to the inhibitory effects of manganese and cobalt. Yeomans et al. [344] showed that the zinc-histidine complex is able to inhibit copper-induced LDL oxidation, but the antioxidant effect of this complex obviously depended on histidine and not zinc because zinc sulfate was ineffective. We proposed another mode of possible antioxidant effect of zinc [345], It has been found that Zn and Mg aspartates inhibited oxygen radical production by xanthine oxidase, NADPH oxidase, and human blood leukocytes. The antioxidant effect of these salts supposedly was a consequence of the acceleration of spontaneous superoxide dismutation due to increasing medium acidity. 

In this study, UV-Vis and 3D fluorescence spectra were used to investigate the catalysis and inhibition of metallic ions on the production of 3-NT and protein in vitro. Our results showed that Co(Fl) and Cu(FI) enhance the production of 3-NT in proteins, but Mn(If) and Ni(n) inhibits its production. 3D-fluorescence showed that Co(FI) could promote Fg nitration in a concentration dependent manner, while Cu(FI) facilitated BSA nitration. Consequently, essential trace metal element for biological systems, such as copper and cobalt salts, have a synergistic action with peroxynitrite on protein nitration. 

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