Tags

Type your tag names separated by a space and hit enter

Reactions of the NO redox forms NO+, *NO and HNO (protonated NO-) with the melatonin metabolite N1-acetyl-5-methoxykynuramine.
J Pineal Res. 2007 Nov; 43(4):382-8.JP

Abstract

The different NO redox forms, NO+, *NO and HNO (=protonated NO-), were compared for their capabilities of interacting with the melatonin metabolite N1-acetyl-5-methoxykynuramine (AMK), using NO+SbF6-, PAPA-NONOate and Angeli's salt as donors of the respective NO species. Particular attention was paid to stability and possible interconversions of the redox forms. *NO formation was followed by measuring the decolorization of 2-(trimethylammonio-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (TMA-PTIO), at different pH values, at which NO+ is, in aqueous solution, either highly unstable (pH 7.4) or relatively stable (pH 2.0). *NO donation by PAPA-NONOate, as indicated by TMA-PTIO decolorization, was similar at either pH and 3-acetamidomethyl-6-methoxycinnolinone (AMMC) was formed as the major product from AMK, at pH 7.4 more efficiently than at pH 2.0. At pH 2.0, TMA-PTIO decolorization by NO+SbF6- was much weaker than by PAPA-NONOate, but AMMC was produced at substantial rates, whereas neither TMA-PTIO decolorization nor AMMC formation was observed with the NO+ donor at pH 7.4. As NO+ is also stable in organic, especially aprotic solvents, NO+SbF6- was reacted with AMK in acetonitrile, ethanol, butanol, and ethyl acetate. In all these cases, AMMC was the only or major product. In ethyl acetate, N1-acetyl-5-methoxy-3-nitrokynuramine (AMNK) was also formed, presumably as a consequence of organic peroxides emerging in that solvent. Presence of tert-butylhydroperoxide in an ethanolic solution of NO+SbF6- and AMK also resulted in AMNK formation, in addition to AMMC and two red-fluoresecent, to date unknown products. However, hydrogen peroxide enhanced *NO-dependent AMMC production from AMK and also from N1-acetyl-N2-formyl-5-methoxykynuramine. HNO donation by Angeli's salt (Na2N2O3) also caused AMMC formation from AMK at pH 7.4, with a somewhat lower efficiency than PAPA-NONOate, but no AMNK nor any other product was detected. Therefore, all three NO congeners are, in principle, capable of nitrosating AMK and forming AMMC, but in biological material the reaction with NO+ is strongly limited by the extremely short life-time of this redox form.

Authors+Show Affiliations

Hardeland R
Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen, Germany. rhardel@gwdg.de
Backhaus C
No affiliation info available
Fadavi A
No affiliation info available

MeSH

Hydrogen-Ion ConcentrationKineticsKynuramineMelatoninNitric Oxide DonorsNitritesNitro CompoundsNitrogen OxidesOxidation-ReductionReactive Nitrogen Species

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17910607

Citation

Hardeland, Rüdiger, et al. "Reactions of the NO Redox Forms NO+, *NO and HNO (protonated NO-) With the Melatonin Metabolite N1-acetyl-5-methoxykynuramine." Journal of Pineal Research, vol. 43, no. 4, 2007, pp. 382-8.
Hardeland R, Backhaus C, Fadavi A. Reactions of the NO redox forms NO+, *NO and HNO (protonated NO-) with the melatonin metabolite N1-acetyl-5-methoxykynuramine. J Pineal Res. 2007;43(4):382-8.
Hardeland, R., Backhaus, C., & Fadavi, A. (2007). Reactions of the NO redox forms NO+, *NO and HNO (protonated NO-) with the melatonin metabolite N1-acetyl-5-methoxykynuramine. Journal of Pineal Research, 43(4), 382-8.
Hardeland R, Backhaus C, Fadavi A. Reactions of the NO Redox Forms NO+, *NO and HNO (protonated NO-) With the Melatonin Metabolite N1-acetyl-5-methoxykynuramine. J Pineal Res. 2007;43(4):382-8. PubMed PMID: 17910607.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Reactions of the NO redox forms NO+, *NO and HNO (protonated NO-) with the melatonin metabolite N1-acetyl-5-methoxykynuramine. AU - Hardeland,Rüdiger, AU - Backhaus,Claudia, AU - Fadavi,Azadeh, PY - 2007/10/4/pubmed PY - 2008/2/27/medline PY - 2007/10/4/entrez SP - 382 EP - 8 JF - Journal of pineal research JO - J Pineal Res VL - 43 IS - 4 N2 - The different NO redox forms, NO+, *NO and HNO (=protonated NO-), were compared for their capabilities of interacting with the melatonin metabolite N1-acetyl-5-methoxykynuramine (AMK), using NO+SbF6-, PAPA-NONOate and Angeli's salt as donors of the respective NO species. Particular attention was paid to stability and possible interconversions of the redox forms. *NO formation was followed by measuring the decolorization of 2-(trimethylammonio-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (TMA-PTIO), at different pH values, at which NO+ is, in aqueous solution, either highly unstable (pH 7.4) or relatively stable (pH 2.0). *NO donation by PAPA-NONOate, as indicated by TMA-PTIO decolorization, was similar at either pH and 3-acetamidomethyl-6-methoxycinnolinone (AMMC) was formed as the major product from AMK, at pH 7.4 more efficiently than at pH 2.0. At pH 2.0, TMA-PTIO decolorization by NO+SbF6- was much weaker than by PAPA-NONOate, but AMMC was produced at substantial rates, whereas neither TMA-PTIO decolorization nor AMMC formation was observed with the NO+ donor at pH 7.4. As NO+ is also stable in organic, especially aprotic solvents, NO+SbF6- was reacted with AMK in acetonitrile, ethanol, butanol, and ethyl acetate. In all these cases, AMMC was the only or major product. In ethyl acetate, N1-acetyl-5-methoxy-3-nitrokynuramine (AMNK) was also formed, presumably as a consequence of organic peroxides emerging in that solvent. Presence of tert-butylhydroperoxide in an ethanolic solution of NO+SbF6- and AMK also resulted in AMNK formation, in addition to AMMC and two red-fluoresecent, to date unknown products. However, hydrogen peroxide enhanced *NO-dependent AMMC production from AMK and also from N1-acetyl-N2-formyl-5-methoxykynuramine. HNO donation by Angeli's salt (Na2N2O3) also caused AMMC formation from AMK at pH 7.4, with a somewhat lower efficiency than PAPA-NONOate, but no AMNK nor any other product was detected. Therefore, all three NO congeners are, in principle, capable of nitrosating AMK and forming AMMC, but in biological material the reaction with NO+ is strongly limited by the extremely short life-time of this redox form. SN - 0742-3098 UR - https://www.unboundmedicine.com/medline/citation/17910607/Reactions_of_the_NO_redox_forms_NO+__NO_and_HNO__protonated_NO___with_the_melatonin_metabolite_N1_acetyl_5_methoxykynuramine_ DB - PRIME DP - Unbound Medicine ER -