Enzymatic breakage of dimethylsulfoniopropionate—a signature molecule for life at sea

•Dimethylsulfoniopropionate (DMSP) is made in large amounts by marine eukaryotes.•Various marine microorganisms can catabolise this zwitterion in a range of different ways.•Recent studies reveal novel enzymatic mechanisms for DMSP cleavage or demethylation.•We review these findings, in relation to earlier genetic studies on this process. Largely using gene-based evidence, the last few years have seen real insights on the diverse ways in which different microbes break down dimethylsulfoniopropionate, an abundant anti-stress molecule that is made by marine algae, some corals and a few angiosperms. Here, we review more recent advances in which in vitro biochemical tools—including structural determinations—have shed new light on how the corresponding enzymes act on DMSP. These have revealed how enzymes in very different polypeptide families can act on this substrate, often by novel ways, and with broader implications that extend from enzymatic mechanisms to microbial ecology.