Thioredoxins are proteins that act as antioxidants by facilitating the reduction of other proteins by cysteine thiol-disulfide exchange. Thioredoxins are found in nearly all known organisms and are essential for life in mammals.This is an enzyme I became familiar with in my days as a plant biochemist, long before Wikipedia (or the internet, for that matter) was invented. Thioredoxin is “everywhere,” including the regulation of the most abundant protein on earth, Rubisco (the enzyme that “fixes” carbon dioxide making life possible for every plant and animal, including us). Thioredoxin will make sure that the chain of events keeping proteins in their “right” reduction state is kept well oiled. Or, in other words, thioredoxin will facilitate the reduction of your skin proteins by cysteine (in a disulfide bond|thiol-disulfide exchange). The Trx (thioredoxin) and Grx (glutaredoxin) systems control cellular redox potential, keeping a reducing thiol-rich intracellular state, which no generation of reactive oxygen species signals through thiol redox control mechanisms.