Redox chemistry and chemical biology of H2S, hydropersulfides, and derived species: implications of their possible biological activity and utility

Abstract

Hydrogen sulfide (H2S) is an endogenously generated and putative signaling/effector molecule. Despite its numerous reported functions, the chemistry by which it elicits its functions is not understood. Moreover, recent studies allude to the existence of other sulfur species besides H2S that may play critical physiological roles. Herein, the basic chemical biology of H2S as well as other related or derived species is discussed and reviewed. This review particularly focuses on the per- and polysulfides which are likely in equilibrium with free H2S and which may be important biological effectors themselves.

Keywords: Hydrogen sulfide; Persulfides; Polysulfides; Thiol redox; Thiols.

Figure 1

Generation of Cys-SSH from Cys-SS-Cys.

Figure 2

Possible mechanisms of ⁻SCN formation from reaction of CN⁻ with a persulfide.

Figure 3

Resonance stability of the perthiyl radical

Figure 4

Possible/putative biologically relevant reactions of persulfides.

Figure 5

H₂O₂-mediated oxidations under basic and acidic conditions.

Figure 6

Possible role of protein persulfide formation.

Scheme 1

Possible roles of persulfide and protein persulfide generation.