In methanobacteria (2R)-phospho-3-sulfolactate synthase (ComA) catalyses the first step of the biosynthesis of coenzyme M from phosphoenolpyruvate (P-enolpyruvate). This novel enzyme catalyses the stereospecific Michael addition of sulfite to P-enolpyruvate, forming L-2-phospho-3-sulfolactate (PSL). It is suggested that the ComA-catalysed reaction is analogous to those reactions catalysed by beta-elimination enzymes that proceed through an enolate intermediate [1].

1: Identification of coenzyme M biosynthetic phosphosulfolactate synthase: a new family of sulfonate-biosynthesizing enzymes. Graham DE, Xu H, White RH; J Biol Chem 2002;277:13421-13429. PMID:11830598