Editing Disulfide (section)

====In bacteria and archaea====
Disulfide bonds play an important protective role for [[bacteria]] as a reversible switch that turns a protein on or off when bacterial cells are exposed to [[oxidation]] reactions. [[Hydrogen peroxide]] ([[hydrogen|H]]<sub>2</sub>[[oxygen|O]]<sub>2</sub>) in particular could severely damage [[DNA]] and kill the [[bacteria|bacterium]] at low concentrations if not for the protective action of the SS-bond. [[Archaea]] typically have fewer disulfides than higher organisms.<ref>{{cite journal|last1=Ladenstein|first1=R.|last2=Ren|first2=B.|year=2008|title=Reconsideration of an early dogma, saying "there is no evidence for disulfide bonds in proteins from archaea"|journal=[[Extremophiles (journal)|Extremophiles]]|volume=12|issue=1|pages=29–38|doi=10.1007/s00792-007-0076-z|pmid=17508126|s2cid=11491989}}</ref>