| The kinetics of thiol-mediated decomposition of S-nitrosothiols. | |
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MedLine Citation:
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PMID: 17025266 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The reaction of sulfhydryl (SH)-containing molecules (thiols) with S-nitrosothiols (RSNO) has been shown to be of biological importance. Biologically or therapeutically relevant thiols generally have a pKa value ranging from 8 to 10 for the SH group. In addition, some of these thiols contain a carboxyl group and are acidic, which should be considered in studying the reaction between RSNO and thiols. In the present study, the kinetics of thiol-mediated decomposition of RSNO was investigated in a commonly used phosphate buffer, phosphate buffered saline (PBS; containing 6.9 mM phosphates; buffer capacity = 3.8 mM/pH). The thiols studied can be divided into 2 groups, depending on their pH perturbation capacity. The kinetics was studied using a wide range of thiol concentrations (ie, from 0.1 to 10 mM). A high-performance liquid chromatography (HPLC) method was used to determine RSNO concentrations. The results showed that the acidic thiols, including glutathione, captopril, N-acetylcysteine, and tiopronin, stimulated RSNO decomposition at low millimolar concentrations up to 2 mM. The stimulatory effect, however, became attenuated at concentrations higher than 2 mM in PBS. Increasing the concentration of acidic thiols caused a decrease in solution pH, which was attributable to the inhibitory effect at high thiol concentrations. The effect of thiols on the pH of reaction solution, and the resulting bell-shaped rate profiles, can be predicted by a quantitative analysis, from which a comparison of the intrinsic reactivity toward RSNO, among 8 thiols, was possible. The intrinsic reactivity in general followed the Brønsted relation. |
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Authors:
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Teh-Min Hu; Ta-Chuan Chou |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2006-07-28 |
Journal Detail:
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Title: The AAPS journal Volume: 8 ISSN: 1550-7416 ISO Abbreviation: AAPS J Publication Date: 2006 |
Date Detail:
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Created Date: 2006-10-09 Completed Date: 2006-10-24 Revised Date: 2010-09-15 |
Medline Journal Info:
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Nlm Unique ID: 101223209 Medline TA: AAPS J Country: United States |
Other Details:
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Languages: eng Pagination: E485-92 Citation Subset: IM |
Affiliation:
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School of Pharmacy, National Defense Medical Center, Taipei, Taiwan, Republic of China. tmhu@ndmctsgh.edu.tw |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Kinetics* Nitric Oxide / physiology S-Nitrosothiols / chemistry*, metabolism Sulfhydryl Compounds / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/S-Nitrosothiols; 0/Sulfhydryl Compounds; 10102-43-9/Nitric Oxide |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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