In　the　water/n-dodecane　biphasic　reaction　system,　the　influence　of　organic　solvent　treatment　on　the　gene　expression　level　of　isozymes　of　alcohol　dehydrogenase　(ADH)　1~3　was　investigated　to　probe　their　correlation　in　asymmetric　reduction　of　the　substrate　2-octanone　by　Saccharomyces　cerevisiae　type　II.　The　results　showed　that　after　treatment　with　organic　media,　the　relative　expression　level　of　isozymes　of　alcohol　dehydrogenase　(ADH)　varied,　along　with　the　different　properties　shown　in　asymmetric　reduction　of　2-octanone　treatmented　by　Saccharomyces　cerevisiae,　the　gene　expression　level　of　ADH　1　was　severely　inhibited　by　toluene　and　2-octanol,　but　it　was　not　obviously　influenced　by　n-dodecane,　n-octane　and　n-hexane,　while　substantially　enhanced　by　2-octanone.　However,　the　gene　expression　level　of　ADH　2　was　highly　increased　by　toluene　and　2-octanol,　but　inhibited　by　n-dodecane,　n-octane,　n-hexane,　and　2-octanone.　Furthermore,　the　inhibition　of　ADH　1　gene　expression　would　reduce　the　catalytic　activity,　and　inhibition　of　ADH　2　gene　expression　would　improve　the　enantiomeric　selectivity,　while　the　gene　expression　level　of　ADH　3　would　not　influence　both　the　activity　and　selectivity.　The　isozyme　ADH　1　which　has　good　enantio　selectivity　is　the　key　oxidoreductase　for　catalyzing　asymmetric　reduction　of　2-ocatnone　by　Saccharomyces　cerevisiae　type　II,　and　the　isozyme　ADH　2　is　of　poor　enantio　selectivity　while　it　conducts　the　same　reaction.　©　2017,　Science　Press.　All　right　reserved.