This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is ethyl-(S)-3-hydroxyhexanoate:NADP+ 3-oxidoreductase. This enzyme is also called 3-oxo ester (S)-reductase.
Heidlas J, Engel KH, Tressl R (1988). "Purification and characterization of two oxidoreductases involved in the enantioselective reduction of 3-oxo, 4-oxo and 5-oxo esters in baker's yeast". Eur. J. Biochem.172 (3): 633–9. doi:10.1111/j.1432-1033.1988.tb13936.x. PMID3280313.