Involved in aliphatic epoxide carboxylation (PubMed:20302306). Catalyzes the reversible oxidation of (2S)-2-hydroxypropyl-coenzyme M (S-HPC) to 2-oxopropyl-coenzyme M (2-KPC) (PubMed:20302306). The enzyme is highly specific for the S enantiomers (PubMed:20302306). In vitro can also use the aliphatic ketone 2-butanone and the aliphatic alcohol 2-propanol, and shows an inherent stereoselectivity for 2-butanone reduction (PubMed:20302306). (2S)-2-hydroxypropyl-coenzyme M + NAD(+) = 2-oxopropyl-coenzyme M + H(+) + NADH Not inhibited by 2-(2-methyl-2-hydroxypropylthio)ethanesulfonate (M-HPC), an achiral analog of both R-HPC and S-HPC. kcat is 5.5 sec(-1) with R-HPC as substrate. kcat is 25 sec(-1) with S-HPC as substrate. kcat is 11 sec(-1) with 2-KPC as substrate. kcat is 0.044 sec(-1) with 2-butanone as substrate. kcat is 2.0 sec(-1) with 2-propanol as substrate. kcat is 1.0 sec(-1) with (R)-2-butanol as substrate. kcat is 2.6 sec(-1) with (S)-2-butanol as substrate. Homotetramer. Enantioselectivity is dictated largely by changes in Km. Belongs to the short-chain dehydrogenases/reductases (SDR) family.