Reversible thiol modification is a major component of the modulation of cell-signaling
pathways by reactive oxygen species. Hydrogen peroxide, peroxynitrite, or lipid
hydroperoxides are all able to oxidize cysteines to form cysteine sulfenic acids; this reactive
intermediate can be directly reduced to thiol by cellular reductants such as thioredoxin or
further participate in disulfide bond formation with glutathione or cysteine residues in the
same or another protein. To identify the direct protein targets of cysteine modification and the …