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Reactions of .N02 with chromium(III) complexes with histamine and pyridoxamine ligands studied by the stopped-flow technique

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Bibliographic Details
Title: Reactions of .N02 with chromium(III) complexes with histamine and pyridoxamine ligands studied by the stopped-flow technique
Source: Analytical Biochemistry. 350(2):256-262
Publisher Information: 2006.
Publication Year: 2006
Subject Terms: SIN-1, NO2 radical, Kinetic mechanisms, Cr(III) complexes with histamine and pyridoxamine
Description: This study demonstrated the direct formation of the nitrogen dioxide (radical dotNO2) radical during the decomposition of 3-morpholinosydnonimine (SIN-1) in biological buffer 4-morpholinoethanosulfone acid solution. Consequently, at approximately pH 4, SIN-1 can be used successfully as a source of radical dotNO2. This conclusion is drawn from a comparison of the reactions of cis-[Cr(C2O4)(L– L)(OH2)2]+, where L–L denotes pyridoxamine (Hpm) or histamine (hm), with the gaseous radical dotNO2 radical obtained by two methods: from SIN-1 and from a simple redox reaction. These reactions were investigated using the stopped-flow technique. The measurements were carried out at temperatures ranging from 5 to 25 °C over a pH range from 6.52 to 9.11 for cis-[Cr(C2O4)(Hpm) (OH2)2]+ and from 6.03 to 8.15 for cis-[Cr(C2O4)(hm)(OH2)2] +. We also determined the thermodynamic activation parameter (Ea) and the uptake mechanism for each of the coordination compounds studied.
Document Type: Article
Language: English
ISSN: 0003-2697
DOI: 10.1016/j.ab.2005.12.01610.1016/j.ab.2005.12.016
Accession Number: edsair.dris...02463..260f81a3c7c183c5aaddd85f8e0100d8
Database: OpenAIRE
Description
Abstract:This study demonstrated the direct formation of the nitrogen dioxide (radical dotNO2) radical during the decomposition of 3-morpholinosydnonimine (SIN-1) in biological buffer 4-morpholinoethanosulfone acid solution. Consequently, at approximately pH 4, SIN-1 can be used successfully as a source of radical dotNO2. This conclusion is drawn from a comparison of the reactions of cis-[Cr(C2O4)(L– L)(OH2)2]+, where L–L denotes pyridoxamine (Hpm) or histamine (hm), with the gaseous radical dotNO2 radical obtained by two methods: from SIN-1 and from a simple redox reaction. These reactions were investigated using the stopped-flow technique. The measurements were carried out at temperatures ranging from 5 to 25 °C over a pH range from 6.52 to 9.11 for cis-[Cr(C2O4)(Hpm) (OH2)2]+ and from 6.03 to 8.15 for cis-[Cr(C2O4)(hm)(OH2)2] +. We also determined the thermodynamic activation parameter (Ea) and the uptake mechanism for each of the coordination compounds studied.
ISSN:00032697
DOI:10.1016/j.ab.2005.12.01610.1016/j.ab.2005.12.016