Sulfoxides undergo deoxygenation to give sulfides.  Typically metal complexes are used to catalyze the reaction, using hydrosilanes as the stoichiometric reductant. The deoxygenation of dimethylsulfoxide is catalyzed by DMSO reductase, a molybdoenzyme:
:OSMe  +  2e  +  2 H  →   SMe  +  HO