Oxidation of biological thiols by highly reactive disulfide-S-oxides.

Oxidative stress involves the generation of a number of reactive species, among them 'reactive oxygen species' and 'reactive nitrogen species'. Recent reports have indicated that disulfide-S-monoxides (thiosulfinates) and disulfide-S-dioxides (thiosulfonates) are formed under conditions of oxidative stress. We have now been able to demonstrate that these species are highly reactive and rapidly oxidise thiols. Glutathione and cysteine were oxidised to mixed disulfides by the action of disulfide-S-oxides. Oxidative attack on the zinc/sulfur protein metallothionein with concomitant zinc release was readily accomplished by these 'reactive sulfur species' whereas hydrogen peroxide showed minimal zinc release.