Hydroxylamines inhibit tyrosine oxidation and nitration: The role of their respective nitroxide radicals

Samuni, Amram; Goldstein, Sara

doi:10.1016/j.freeradbiomed.2020.08.022

Cited by 6 publications

(3 citation statements)

References 61 publications

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“…Recently, it was shown that hydroxylamine derivatives of piperidine nitroxides effectively inhibited the oxidation and nitration of tyrosine, initiated by HRP/H 2 O 2 and HRP/H 2 O 2 /nitrite. Interestingly, the piperidine hydroxylamines turned out to be such effective antioxidants as the corresponding nitroxides [ 48 ]. The combination of zeaxanthin with lipophilic nitroxides effectively protected against lipid peroxidation induced by singlet oxygen.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Piperidine Nitroxides on the Properties of Metalloproteins in Human Red Blood Cells

Bujak-Pietrek,

Pieniazek,

Gwozdzinski

et al. 2023

Molecules

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Nitroxides are stable, low molecular-weight radicals containing a nitroxide group that has an unpaired electron. The presence of a nitroxide group determines their redox properties. The effect of the piperidine nitroxides, Tempo, Tempol, and Tempamine, on metalloproteins (hemoglobin, superoxide dismutase, catalase) and lactate dehydrogenase in red blood cells was investigated in this research. In addition, the level of lipid peroxidation and the level of protein carbonyl groups were examined as indicators of the effect of oxidative stress. Nitroxides increased superoxide dismutase activity and oxidized hemoglobin to methemoglobin, and also slightly decreased the catalase activity of red blood cells treated with nitroxides. Tempol significantly decreased lactate dehydrogenase activity. All three nitroxides had no effect on membrane lipid peroxidation and protein oxidation. Our results confirm that nitroxides have both antioxidant and prooxidative effects in human red blood cells. The piperidine nitroxides do not initiate the oxidation of proteins and lipids in the membranes of human red blood cells.

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Section: Discussionmentioning

confidence: 99%

The Effect of Piperidine Nitroxides on the Properties of Metalloproteins in Human Red Blood Cells

Bujak-Pietrek,

Pieniazek,

Gwozdzinski

et al. 2023

Molecules

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“…In addition to the synthesis of chiral amines, the enantioselective reduction of oximes can also produce chiral hydroxylamines. These compounds possess a N-O bond which has been associated with interesting biological properties [25][26][27] and can act as one-atom nitrogen source for metal-catalyzed cycloaddition reactions [28]. In recent years, several groups studied the enantioselective reduction of oximes taking advantage of the borane-mediated reductions, metal-catalyzed hydrogenation/hydrogenolysis and hydride transfer as described below.…”

Section: Enantioselective Reduction Of Oximesmentioning

confidence: 99%

Reduction of Oximes and Hydrazones: Asymmetric and Diastereoselective Approaches

Ribeiro

Alves

Cardoso

et al. 2021

COC

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: The asymmetric reduction of oximes and hydrazones is an attractive and versatile strategy for the synthesis of chiral amines, which are valuable building blocks in organic synthesis. This review summarizes the relevant developments made in the last decade on the enantioselective and diastereoselective reduction of oximes and hydrazones involving metal-catalyzed hydrogenation/hydrogenolysis reactions, hydride donor reactions, and electrochemical reactions.

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“…The present study demonstrates that cyclic hydroxylamines (RNO-H) do not react directly with peroxynitrite, but rather indirectly with the radicals formed during its self-decomposition ( Scheme 1 ). In addition, due to multiple competing reactions of the oxidized forms of RNO-H, i.e., nitroxide (RNO • ) and oxoammonium cation (RN + =O), with • NO 2 and ONOO − , and the formation of • OH and • NO 2 by other oxidizing systems [ 8 , 13 ], the determination of [RNO • ] thus accumulated does not validly reflect the formation of peroxynitrite and cannot be used for its quantitative or even qualitative determination.…”

Section: Introductionmentioning

confidence: 99%

Cyclic Hydroxylamines as Monitors of Peroxynitrite and Superoxide-Revisited

Samuni

Goldstein

2021

Antioxidants

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There is a considerable need for methods that allow quantitative determination in vitro and in vivo of transient oxidative species such as peroxynitrite (ONOOH/ONOO–) and superoxide (HO2•/O2•−). Cyclic hydroxylamines, which upon oxidation yield their respective stable nitroxide radicals, have been suggested as spin probes of peroxynitrite and superoxide. The present study investigated this approach by following the kinetics of peroxynitrite decay in the absence and presence of various 5-membered and 6-membered ring hydroxylamines, and comparing the yield of their respective nitroxides using electron paramagnetic spectroscopy. The results demonstrate that hydroxylamines do not react directly with peroxynitrite, but are oxidized to their respective nitroxides by the radicals formed during peroxynitrite self-decomposition, namely •OH and •NO2. The accumulated nitroxides are far below their expected yield, had the hydroxylamines fully scavenged all these radicals, due to multiple competing reactions of the oxidized forms of the hydroxylamines with •NO2 and ONOO–. Therefore, cyclic hydroxylamines cannot be used for quantitative assay of peroxynitrite in vitro. The situation is even more complex in vivo where •OH and •NO2 are formed also via other oxidizing reactions systems. The present study also compared the yield of accumulated nitroxides under constant flux of superoxide in the presence of various cyclic hydroxylamines. It is demonstrated that certain 5-membered ring hydroxylamines, which their respective nitroxides are poor SOD-mimics, might be considered as stoichiometric monitors of superoxide in vitro at highest possible concentrations and pH.

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Hydroxylamines inhibit tyrosine oxidation and nitration: The role of their respective nitroxide radicals

Cited by 6 publications

References 61 publications

The Effect of Piperidine Nitroxides on the Properties of Metalloproteins in Human Red Blood Cells

The Effect of Piperidine Nitroxides on the Properties of Metalloproteins in Human Red Blood Cells

Reduction of Oximes and Hydrazones: Asymmetric and Diastereoselective Approaches

Cyclic Hydroxylamines as Monitors of Peroxynitrite and Superoxide-Revisited

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