Identification of Cu+ as the effective reagent in nitric oxide formation from S-nitrosothiols (RSNO)

Nitric oxide induces Zn2+ release from metallothionein by destroying zinc–sulphur clusters without concomitant formation of S-nitrosothiol

“…As to the alternative pathway via S-nitrosylation, different reaction mechanisms have been proposed for the decay of Snitrosothiols and formation of disulphides [28,35,36]. Disulphides can be formed via a simple radical pathway by combination of two sulphur-centred radicals (RSd), resulting from the initial decay of S-nitrosothiols with release of NO, and by reaction of RSd with RSNO [28].…”

“…Disulphides can be formed via a simple radical pathway by combination of two sulphur-centred radicals (RSd), resulting from the initial decay of S-nitrosothiols with release of NO, and by reaction of RSd with RSNO [28]. Recently, it has been shown that the decomposition of S-nitrosothiols in aqueous solution is brought about by Cu + , generated by reduction of Cu# + by thiolate ion [35]. Thiols (as thiolate) have a dual effect on the decomposition of S-nitrosothiols, (i) as a reducing agent generating Cu + and (ii) as a complexing agent for Cu# + which is then less available for reduction, the balance of these effects depending on the structure and concentration of the thiol [36].…”

“…Thiols (as thiolate) have a dual effect on the decomposition of S-nitrosothiols, (i) as a reducing agent generating Cu + and (ii) as a complexing agent for Cu# + which is then less available for reduction, the balance of these effects depending on the structure and concentration of the thiol [36]. It has clearly been shown [35] that in the absence of light no reaction occurs, except for a very slow thermal decomposition, when metal ions are removed (e.g. by EDTA) or when Cu + is removed specifically with neocuproine.…”

The Reaction of Superoxide Radicals withS-Nitrosoglutathione and the Products of Its Reductive Heterolysis

“…Release of NO ⅐ from S-nitrosothiols can be achieved by thiols or reduction, e.g. by Cu(I) formed from trace Cu(II) via thiols or ascorbate (7)(8)(9)(10)(11)(12), or by a GSNO 1 reductase (13). However, the potential role of superoxide radicals in this regard is unclear.…”

Structural Features of Proteins Responsible for Resistance of Tryptophan Residues to Nitrosylation

“…Denitrosation by external denitrosilase leads to a rapid decrease in the fraction of the nitrosated residues and might induce an intermittent flow of nitrite or thionitrites. The information acquired previously in response to a signal from outside (denitrosilase) is also processed and transmitted to neighbouring structures as a nitrite or RSNO flow, which can be reduced back to NO (23)(24)(25)(26).…”