Chemistry of Hydrogen Sulfide-Pathological and Physiological Functions in Mammalian Cells.

Hydrogen sulfide (H 2 S) was recognized as a gaseous signaling molecule, similar to nitric oxide (-NO) and carbon monoxide (CO). The aim of this review is to provide an overview of the formation of hydrogen sulfide (H 2 S) in the human body. H 2 S is synthesized by enzymatic processes involving cysteine and several enzymes, including cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), cysteine aminotransferase (CAT), 3-mercaptopyruvate sulfurtransferase (3MST) and D-amino acid oxidase (DAO). The physiological and pathological effects of hydrogen sulfide (H 2 S) on various systems in the human body have led to extensive research efforts to develop appropriate methods to deliver H 2 S under conditions that mimic physiological settings and respond to various stimuli. These functions span a wide spectrum, ranging from effects on the endocrine system and cellular lifespan to protection of liver and kidney function. The exact physiological and hazardous thresholds of hydrogen sulfide (H 2 S) in the human body are currently not well understood and need to be researched in depth. This article provides an overview of the physiological significance of H 2 S in the human body. It highlights the various sources of H 2 S production in different situations and examines existing techniques for detecting this gas.