Involved in the dimethyl sulfide degradation pathway (PubMed:12686641). Activates the expression of sfnG and sfnF. Under sulfate limitation conditions, it is transcriptionally activated by the LysR-type transcriptional regulator, CysB. Cells lacking this gene are still able to convert dimethyl sulfide (DMS) to dimethyl sulfone (DMSO2) under sulfate limitation, suggesting that the conversion of dimethyl sulfone (DMSO2) to methanesulfonate (MSA) is interrupted in this mutant.