Nitric Oxide Reactivity of [2Fe-2S] Clusters Leading to H2S Generation

详细信息    查看全文

• 作者：Camly T. Tran ; Paul G. Williard ; Eunsuk Kim
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：August 27, 2014
• 年：2014
• 卷：136
• 期：34
• 页码：11874-11877
• 全文大小：257K
• ISSN：1520-5126

文摘

The crosstalk between two biologically important signaling molecules, nitric oxide (NO) and hydrogen sulfide (H₂S), proceeds via elusive mechanism(s). Herein we report the formation of H₂S by the action of NO on synthetic [2Fe-2S] clusters when the reaction environment is capable of providing a formal H^{鈥?/sup> (e鈥?/sup>/H+). Nitrosylation of (NEt₄)₂[Fe₂S₂(SPh)₄] (1) in the presence of PhSH or tBu₃PhOH results in the formation of (NEt₄)[Fe(NO)₂(SPh)₂] (2) and H₂S with the concomitant generation of PhSSPh or tBu₃PhO鈥?/sup>. The amount of H₂S generated is dependent on the electronic environment of the [2Fe-2S] cluster as well as the type of H鈥?/sup> donor. Employment of clusters with electron-donating groups or H鈥?/sup> donors from thiols leads to a larger amount of H₂S evolution. The 1/NO reaction in the presence of PhSH exhibits biphasic decay kinetics with no deuterium kinetic isotope effect upon PhSD substitution. However, the rates of decay increase significantly with the use of 4-MeO-PhSH or 4-Me-PhSH in place of PhSH. These results provide the first chemical evidence to suggest that [Fe-S] clusters are likely to be a site for the crosstalk between NO and H₂S in biology.}