Mediates cleavage of dimethylsulfonioproprionate (DMSP) into dimethyl sulfide (DMS) and acrylate. DMS is the principal form by which sulfur is transported from oceans to the atmosphere and is a key component of the ocean sulfur cycle. S,S-dimethyl-beta-propiothetin = acrylate + dimethyl sulfide + H(+) Homotetramer. Expressed at low level. At least 10 million metric tons of volatile dimethyl sulfide (DMS) are released into the atmosphere annually by the dimethylsulfonioproprionate lyase in oceans. It is a component of the tangy aroma of the seaside and functions as a chemical attractant that guides various marine animals, such as sea birds, invertebrates, and some mammals, toward potential food supplies. DMS oxidation products act as condensation nuclei, causing water molecules to coalesce, with possible effects on local climate through enhanced cloud formation. Belongs to the aspartate/glutamate racemases family. ALMA1 subfamily.