Reduces the C=C double bonds of alpha, beta unsaturated enones, but has no activity on enones with an endocyclic C=C double-bond. Shows a high specificity for NADPH as the hybrid donor. Substrates are 1-nitrocyclohexene, 2-methylpentenal, trans-cinnamaldehyde, methyl-trans-2-methylcinnamaldehyde, trans-2-nonenal and 1-octen-3-one. Reduced activity with aplha-methyl transcinnamaldehyde, 1-cyclohexene-1-carboxaldehyde, methyl crotonate, (R)-pulegone, and dimethyl itaconate and no activity with maleimides, citral, (5R)- or (5S)-carvone, (S)-perillyl alcohol, and substituted cyclohexenones and cyclopentenones (PubMed:17945329, Ref.3). May also act as a allyl-alcohol dehydrogenase by catalyzing the dehydrogenation of secondary allylic alcohols rather than saturated secondary alcohols. Allyl-alcohol dehydrogenase is specific for the S-stereoisomer of the alcohols (PubMed:11117876). an n-alkanal + NADP(+) = an alk-2-enal + H(+) + NADPH kcat is 3.3 sec(-1) for (R)-pulegone at pH 7.0. kcat is 2.8 sec(-1) for (S)-pulegone at pH 7.0. kcat is 1.3 sec(-1) for NADPH at pH 7.3. kcat is 1.46 sec(-1) for 1-nitrocyclohexene at pH 7.3. kcat is 9.2 sec(-1) for 2-methylpentenal at pH 5.4. kcat is 0.66 sec(-1) for 2-methylpentenal at pH 7.3. kcat is 1.1 sec(-1) for methyl-trans-2-methylcinnamaldehyde at pH 7.3. Optimum pH is 5.4 with 1-nitrocyclohexene as substrate. Homodimer. There are no hydrogen bonds between the substrate tested and the crystalized protein (Ref.4). The reduction of pulegone shows no sterospecificity and only the pro-4R hydrogen of NADPH is incorporated into the C=C double bond of pulegone (Ref.3). Belongs to the NADP-dependent oxidoreductase L4BD family. PubMed:11117876 showed an allyl-alcohol dehydrogenase activity on (2S,4S)-carveol while PubMed:17945329 and Ref.4 showed an exclusive enone reductase activity.