Detection of hydrogen sulfide in biological samples: Current and future
ABSTRACT Evaluation of: Levitt MD, Abdel-Rehim MS, Furne J. Free and acid-labile hydrogen sulfide concentrations in mouse tissues: anomalously high free hydrogen sulfide in aortic tissue. Antioxid. Redox Signal. DOI: 10.1089/ars.2010.3525 (2010) (Epub ahead of print). Hydrogen sulfide (H(2)S), known as a pungent toxic gas, has recently emerged as a novel critical mediator in the cardiovascular system, the nervous system and various biological signaling functions, as well as a therapeutic agent. However, much less certainty exists regarding biological levels of H(2)S in these systems and during disease. Many papers have reported various methods of measuring the levels of sulfide through different techniques both in vitro and in vivo. Complicating this matter is the fact that sulfide exists in multiple forms - free sulfides such as S(2) (-), HS(-), H(2)S, acid-labile and bound sulfides. These different forms of sulfide make quantitative measurement of bioavailable H(2)S difficult and have led to variable reported levels in the literature. The sensitive detection of sulfide in its multiple forms is needed to establish reliable bioavailable concentrations of sulfide species in order to understand their role in various aspects of physiology and pathology, and to address possible therapeutic approaches. A recent method by Levitt et al. describes a unique gas chromatography chemiluminescence-based technique to measure free and acid-labile H(2)S in multiple tissues from mouse.
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ABSTRACT: Background: Owing to recent discoveries of many hydrogen sulfide-mediated physiological processes, sulfide biology is in the focus of scientific research. However, the promiscuous chemical properties of sulfide pose complications for biological studies, which led to accumulation of controversial observations in the literature. Scope of review: We intend to provide an overview of fundamental thermodynamic and kinetic features of sulfide redox- and coordination-chemical reactions and protonation equilibria in relation to its biological functions. In light of these chemical properties we review the strengths and limitations of the most commonly used sulfide detection methods and recently developed fluorescent probes. We also give a personal perspective on blood and tissue sulfide measurements based on proposed biomolecule-sulfide interactions and point out important chemical aspects of handling sulfide reagent solutions. Major conclusions: The diverse chemistries of sulfide detection methods resulted in orders of magnitude differences in measured physiological sulfide levels. Investigations that were aimed to dissect the underlying molecular reasons responsible for these controversies made the important recognition that there are large sulfide reserves in biological systems. These sulfide pools are tightly regulated in a dynamic manner and they are likely to play a major role in regulation of endogenous-sulfide-mediated biological functions and avoiding toxic side effects. General significance: Working with sulfide is challenging, because it requires considerable amounts of chemical knowledge to adequately handle reagent sulfide solutions and interpret biological observations. Therefore, we propose that a rigorous chemical approach could aid the reconciliation of the increasing number of controversies in sulfide biology. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn.Biochimica et Biophysica Acta 06/2013; 1840(2). DOI:10.1016/j.bbagen.2013.05.037 · 4.66 Impact Factor