The enzyme is highly specific for (2S)-2-hydroxyalkyl thioethers of CoM, in contrast to EC
1.1.1.268, 2-(R)-hydroxypropyl-CoM dehydrogenase, which is highly specific for the (R)-enantiomer. This enzyme forms component IV of a four-component enzyme system {comprising EC
4.4.1.23 (2-hydroxypropyl-CoM lyase; component I), EC
1.8.1.5 [2-oxopropyl-CoM reductase (carboxylating); component II], EC
1.1.1.268 [2-(R)-hydroxypropyl-CoM dehydrogenase; component III] and EC
1.1.1.269 [2-(S)-hydroxypropyl-CoM dehydrogenase; component IV]} that is involved in epoxyalkane carboxylation in Xanthobacter sp. strain Py2.