Involved in aliphatic epoxide carboxylation (PubMed:9405410, PubMed:10411892). Catalyzes the reversible oxidation of (2S)-2-hydroxypropyl-coenzyme M (S-HPC) to 2-oxopropyl-coenzyme M (2-KPC) (PubMed:10411892, PubMed:20302306). The enzyme is highly specific for the S enantiomers (PubMed:10411892, 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 28 sec(-1) with S-HPC as substrate. kcat is 20 sec(-1) with 2-KPC as substrate. kcat is 2.4 sec(-1) with R-HPC as substrate. Alkene metabolism; propylene degradation. Homodimer (PubMed:9405410). Component IV of the aliphatic epoxide carboxylation complex together with components I, II and III (PubMed:9405410, PubMed:10411892). By aliphatic and chlorinated alkenes. Enantioselectivity is dictated largely by changes in Km. Is difficult to express due to its tendency to form inclusion bodies in heterologous expression systems. Belongs to the short-chain dehydrogenases/reductases (SDR) family.