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Five Nitrogen Oxidation States from Nitro to Amine: Stabilization and Reactivity of a Metastable Arylhydroxylamine Complex.

Author(s): Zsombor-Pindera J; Effaty F; Escomel L; Patrick B; Kennepohl P; Ottenwaelder X;

Redox noninnocent ligands enhance the reactivity of the metal they complex, a strategy used by metalloenzymes and in catalysis. Herein, we report a series of copper complexes with the same ligand framework, but with a pendant nitrogen group that spans five ...

Article GUID: 33124796
Scavenging with TEMPO* to identify peptide- and protein-based radicals by mass spectrometry: advantages of spin scavenging over spin trapping.

Author(s): Wright PJ, English AM

J Am Chem Soc. 2003 Jul 16;125(28):8655-65 Authors: Wright PJ, English AM

Article GUID: 12848573
Superoxide dismutase targets NO from GSNO to Cysbeta93 of oxyhemoglobin in concentrated but not dilute solutions of the protein.

Author(s): Romeo AA, Capobianco JA, English AM

J Am Chem Soc. 2003 Nov 26;125(47):14370-8 Authors: Romeo AA, Capobianco JA, English AM

Article GUID: 14624585
Lipid binding to the carotenoid binding site in photosynthetic reaction centers.

Author(s): Deshmukh SS, Tang K, Kálmán L

J Am Chem Soc. 2011 Oct 12;133(40):16309-16 Authors: Deshmukh SS, Tang K, Kálmán L

Article GUID: 21894992
LC-MS/MS Proteoform Profiling Exposes Cytochrome c Peroxidase Self-Oxidation in Mitochondria and Functionally Important Hole Hopping from Its Heme

Author(s): Kathiresan M; English AM;

LC-MS/MS profiling reveals that the proteoforms of cytochrome c peroxidase (Ccp1) isolated from respiring yeast mitochondria are oxidized at numerous Met, Trp, and Tyr residues. In vitro oxidation of recombinant Ccp1 by H2O2 in the absence of its reducing s...

Article GUID: 30145880
Title:Superoxide dismutase targets NO from GSNO to Cysbeta93 of oxyhemoglobin in concentrated but not dilute solutions of the protein.
Authors:Romeo AA,  Capobianco JA,  English AM
Link:https://www.ncbi.nlm.nih.gov/pubmed/14624585?dopt=Abstract
DOI:10.1021/ja0289752
Category:J Am Chem Soc
PMID:14624585
Dept Affiliation: CHEMBIOCHEM
1 Department of Chemistry and Biochemistry, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec, Canada H3G 1M8.

Description:

Superoxide dismutase targets NO from GSNO to Cysbeta93 of oxyhemoglobin in concentrated but not dilute solutions of the protein.

J Am Chem Soc. 2003 Nov 26;125(47):14370-8

Authors: Romeo AA, Capobianco JA, English AM

Abstract

The role of hemoglobin (Hb) in transmitting the vasodilatory property of NO throughout the vascular system is of much current interest. NO exchange between Hb and low-molecular-weight nitrosothiols such as S-nitrosoglutathione (GSNO) has been speculated and reported in vitro. Previously, we reported that NO delivery from GSNO to Cysbeta93 of human oxyHb is prevented in the presence of the Cu chelators, neocuproine, and DTPA.(1) In the present work, 5 mM solutions of commercial human Hb were found by ICP-MS to contain approximately 20 microM Cu and Zn, suggesting the presence of Cu,Zn-superoxide dismutase (CuZnSOD), which was confirmed by Western blotting. SOD activity measurements were consistent with the presence of approximately 20 microM CuZnSOD monomer in 5 mM Hb solutions, which is the physiological concentrations of these proteins in the red blood cell. Incubation of 3.75 mM oxyHb (15 mM heme; 7.5 mM Cysbeta93) with 3.75 or 7.5 mM GSNO gave rise to 50% or 100% S-nitrosation, respectively, of Cysbeta93 as monitored by FTIR nu(SH) absorption, whereas excess GSNO over Cysbeta93 converted oxyHb to metHb due to the reaction, oxyHb + NO<==>metHb + NO(3)(-). Removal of CuZnSOD by anion-exchange chromatography yielded an oxyHb sample that was unreactive toward GSNO, and replacement with bovine CuZnSOD restored reactivity. Addition of 1 microM GSNO (Cysbeta93/GSNO = 1) to solutions diluted 10(4)-fold from physiological concentrations of oxyHb and CuZnSOD resulted largely in metHb formation. Thus, this work reports the following key findings: CuZnSOD is an efficient catalyst of NO transfer between GSNO and Cysbeta93 of oxyHb; metHb is not detected in oxyHb/GSNO incubates containing close to the physiological concentration (5 mM) of Hb and CuZnSOD when the Cysbeta93/GSNO molar ratio is 0.5 to 1.0, but metHb is detected when the total Hb concentration is low micromolar. These results suggest that erythrocyte CuZnSOD may play a critical role in preserving the biological activity of NO by targeting it from GSNO to Cysbeta93 of oxyHb rather than to its oxyheme.

PMID: 14624585 [PubMed - indexed for MEDLINE]