Purification and characterization of a dimethylsulfoniopropionate cleaving enzyme from Desulfovibrio acrylicus

An enzyme that cleaves the algal osmolyte dimethylsulfoniopropionate to dimethylsulfide and acrylate was purified almost 400-fold from the marine sulfate- and acrylate-reducing bacterium Desulfovibrio acrylicus DSM 10141. Dimethylsulfoniopropionate lyase activity was induced by acrylate and dimethylsulfoniopropionate. At 30 degrees C, the enzyme had a K-m for dimethylsulfoniopropionate of 0.45 mM and a V-max of 2590 mu mol min(-1) mg protein(-1). Dimethylsulfoniopropionate was the only substrate of the enzyme. Among the compounds tested, dimethylsulfoniobutyrate was the most potent inhibitor (K-i = 0.25 mM). On a denaturing polyacrylamide gel, the protein migrated as a single band of 49 kDa.