Able to cleave dimethylsulfonioproprionate (DMSP) in vitro, releasing dimethyl sulfide (DMS). DMS is the principal form by which sulfur is transported from oceans to the atmosphere (PubMed:24395783, PubMed:24967457). The real activity of the protein is however subject to debate and it is unclear whether it constitutes a real dimethylsulfonioproprionate lyase in vivo: the very low activity with DMSP as substrate suggests that DMSP is not its native substrate (PubMed:24760823). S,S-dimethyl-beta-propiothetin = acrylate + dimethyl sulfide + H(+) Zn(2+) probably constitutes the cofactor in vivo. Excess zinc decreases the activity, possibly due to the binding of a second Zn(2+) in the active site. Mn(2+) and Co(2+) strongly increase activity. Homodimer. Belongs to the non-heme iron-dependent dioxygenase family.