Mechanism of Metabolism of S-Nitrosothiols

上一个资助期审查了硫醇、过氧亚硝酸盐和一氧化氮之间相互作用的化学基础。已有研究表明，一氧化氮和硫醇的生物代谢产物S-亚硝硫醇在增强和调节一氧化氮的作用中发挥着不同的作用。这些包括抗血小板功能和血管松弛方面的细胞外效应，也是细胞内酶活性和信号通路的调节。对RSNO的新陈代谢知之甚少。人们通常认为，这些化合物自发地释放一氧化氮，这些化合物可以作为一氧化氮供体在商业上获得。然而，这一假设是错误的，RSNO是稳定的化合物，需要额外的试剂来促进分解。本申请建议研究S-亚硝硫醇与生物靶标的分子相互作用，以更全面地了解它们在生物体系中的作用。这将通过解决三个具有相关特定目的的假说来实现：1)蛋白质硫醇是RSNO的主要细胞内靶标的观察结果使我们促进了RSNO对蛋白质硫醇残基的修饰是由蛋白质硫醇的局部环境控制的。这个特定的目的将提出关键的问题，即是什么使特定的硫醇容易受到RSNO的控制：II)我们观察到血红素蛋白可以直接还原S-亚硝硫醇，这导致我们提出亚铁血红素基团是RSNO代谢的主要部位。在这个特定的目标中，我们将探索血红素部分在控制RSNO释放一氧化氮中所起的作用。Iii)我们对内皮细胞代谢RSNO的观察使我们提出，细胞中存在一条活跃的RSNO代谢途径。这些研究人员将通过不同类型的细胞来研究RSNO代谢的机制。RSNO的生物化学与哮喘、炎症、高血压、细胞凋亡和动脉粥样硬化有关。可以预见，这项研究将对这些重要化合物所起的作用产生新的见解，并有助于新的、更具选择性的有效S-亚硝硫醇的药理开发。

The previous funding period examined the chemical basis for the interactions between thiols, peroxynitrite and nitric oxide. It has become apparent that S-nitrosothiols (RSNO), biological metabolites of nitric oxide and thiols, play divers roles in potentiating and modulating the effects of nitric oxide. These include an anti-platelet function and vessel relaxation in terms of extracellular effects, and is also the intracellular modulation of enzyme activities and signaling pathways. Very little is known about the metabolism of RSNO. It is often assumed that these compounds spontaneously liberate nitric oxide and these compounds are commercially available as nitric oxide donors. However, this assumption is in error and RSNO are stable compounds that require an additional agent to promote decomposition. This application proposes to investigate the molecular interactions of S-nitrosothiols with biological targets to understand more fully their role in biological systems. This will be done by addressing three hypothesis with associated specific aims: 1) The observations that protein thiols are the major intracellular targets of RSNO has led us to promote that the modification of protein thiol residues by RSNO is controlled by the local environment of the protein thiol. This specific aim will ask the crucial questions of what makes a particular thiol susceptible to control by RSNO: II) Our observations that heme proteins can directly reduce S-nitrosothiols have led us to propose that ferrous heme groups are a major site of RSNO metabolism. In this specific aim, we will explore the role played by heme moieties in the control of nitric oxide release from RSNO. III) Our observations concerning the metabolism of RSNO by endothelial cells has led us to propose that cells contain an active metabolic pathway for the metabolism of RSNO. These studiers will investigate the mechanism of RSNO metabolism by various cell types. The biochemistry of RSNO has been linked to asthma, inflammation, hypertension, apoptosis and atherosclerosis. It is envisioned that this study will yield new insights into the roles played by these important compounds and aid pharmacological development of new and more selectively potent S- nitrosothiols.