Question

compounds which liberate h2s gas when treated with acid​

Answer 1

Answer:

metal

when react with

acid it liberate

hydrogen gas

i hope it helps you

Answer 2

Answer:

Hydrogen sulfide (H2S) is a newly recognized signaling molecule with very potent cytoprotective actions. The fields of H2S physiology and pharmacology have been rapidly growing in recent years, but a number of fundamental issues must be addressed to advance our understanding of the biology and clinical potential of H2S in the future. Hydrogen sulfide releasing agents (also known as H2S donors) have been widely used in the field. These compounds are not only useful research tools, but also potential therapeutic agents. It is therefore important to study the chemistry and pharmacology of exogenous H2S and to be aware of the limitations associated with the choice of donors used to generate H2S in vitro and in vivo. In this review we summarized the developments and limitations of current available donors including H2S gas, sulfide salts, garlic-derived sulfur compounds, Lawesson’s reagent/analogs, 1,2-dithiole-3-thiones, thiol-activated donors, photo-caged donors, and thioamino acids. Some biological applications of these donors were also discussed.

1. INTRODUCTION

Hydrogen sulfide (H2S), first discovered in 1777 by Carl Wilhelm Scheele, has been traditionally known as a toxic air pollutant with the characteristic odor of rotten eggs. However, this gaseous molecule has been recently recognized as a member of the gasotransmitter family along with its congeners nitric oxide (NO) and carbon monoxide (CO).1–8 The production of H2S in mammalian systems has been attributed to at least three enzymes: cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfur-transferase (MPST) (Scheme 1).9–13 CBS is found predominantly in the brain, nervous system and liver. It converts cysteine and homocysteine to cystathionine and releases H2S. In comparison, CSE activity is higher than CBS in aorta, portal vein and other vascular tissue. CSE is responsible for H2S production in the vasculature and heart through a reaction involving the generation of L-cysteine, pyruvate, and ammonia from L-cystathionine and cysteine. MPST is mainly localized in mitochondria.14 Kimura and coworkers demonstrated that MPST, together with cysteine aminotransferase (CAT), produces H2S from cysteine in the presence of α–ketoglutarate.15 It has also been reported that MPST can convert D-cysteine to H2S in the presence of D-amino acid oxidase.16 Although the expression of these enzymes is tissue-specific, they all convert cysteine or cysteine derivatives to H2S. These enzymes work collectively and precisely regulate H2S levels in tissues, and therefore are crucial for H2S homeostasis.