Disulfide

In chemistry, a disulfide (or disulphide in British English) is a compound containing a R−S−S−R′functional group or the S2−2anion. In inorganic chemistry, the anion appears in the common mineral pyrite but is otherwise rare. Compounds of the form R−S−S−H are usually called persulfides instead.

Disulfide bridges also appear as a common post-translational modification in proteins.