Able to cleave dimethylsulfonioproprionate (DMSP), releasing dimethyl sulfide (DMS) and acrylate. DMS is the principal form by which sulfur is transported from oceans to the atmosphere. S,S-dimethyl-beta-propiothetin = acrylate + dimethyl sulfide + H(+) Binds 1 Fe(2+) ion per subunit. kcat is 18,25 sec(-1) with dimethylsulfonioproprionate (in the presence of Fe(2+)). kcat is 17.33 sec(-1) with dimethylsulfonioproprionate (in the presence of Mn(2+)). Optimum pH is 8.0. Homodimer. Up-regulated by pre-growth of cells with dimethylsulfonioproprionate (DMSP). Decreased production of dimethyl sulfide (DMS). Belongs to the non-heme iron-dependent dioxygenase family.