The nitroxyl anion (NO. ), respectively, can lead to oxidation, hydroxylation, nitration, and nitrosation of biomolecules (1). Although a substantial literature exists on the putative biological effects of other RNOS, few studies have focused on nitroxyl (NO Ϫ ), the one electron reduction product of NO. Several reports suggest that NO Ϫ (or its conjugate acid, HNO) can be generated from chemical reactions that occur in vivo (2, 3) including oxidation of L-arginine by tetrahydrobiopterin-free nitric oxide synthase (NOS) (4 -6) and decomposition of Snitrosothiols (7, 8). Taken together, these studies indicate that the chemistry of NO Ϫ is an essential component of the redox chemistry of NO in biological systems.Angeli's salt (AS) is the most commonly used synthetic donor in the study of NO Ϫ effects under biological conditions (9). At physiological pH and temperature, AS spontaneously decomposes to HNO and nitrite with a half-life of 2.5 min,The cytotoxic effects of AS are several orders of magnitude greater than those of other RNOS and are comparable to alkylhydroperoxides (10), suggesting that NO Ϫ formation in vivo could have deleterious consequences. In a myocardial ischemiareperfusion model, treatment with AS markedly increased infarct area (11). In contrast, NO, either from a donor or from oxidation of NO Ϫ in the presence of an electron acceptor, afforded protection in the same model. In the present report, the chemistry of AS is compared with that of ONOO Ϫ and NO/N 2 O 3 to gain insight into the biological mechanisms in which the chemistry of NO Ϫ could be involved. MATERIALS AND METHODSAngeli's salt (Na 2 N 2 O 3 ) was synthesized as described previously (10). The NONOate, DEA/NO (NaEt 2 NN(O)NO), was a generous gift from Dr. Joseph Saavedra (National Cancer Institute, Frederick, MD). Stock solutions (ϳ10 mM) of AS and DEA/NO were prepared in 10 mM NaOH and stored at Ϫ20°C (12). Peroxynitrite was synthesized by mixing solutions of 0.5 M NO 2 Ϫ in 0.5 M HCl and 0.5 M hydrogen peroxide (H 2 O 2 ) followed by rapid quenching in 1 M NaOH, as described previously (13). The resulting basic solution was exposed to MnO 2 to remove excess H 2 O 2 , which was reduced to Ͻ1% per mol of ONOO Ϫ . After filtering, aliquots were stored at Ϫ20°C for less than 2 weeks. Directly prior to use, the concentrations of these RNOS donors in 10 mM NaOH were
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.