NADPH-dependent oxidoreductase which catalyzes the reduction of a variety of compounds bearing carbonyl groups including ketosteroids, alpha-dicarbonyl compounds, aldehydes, aromatic ketones and quinones. Reduces all-trans-retinal and 9-cis retinal. Reduces 3-ketosteroids and benzil into 3alpha-hydroxysteroids and S-benzoin, respectively, in contrast to the stereoselectivity of primates DHRS4s which produce 3beta-hydroxysteroids and R-benzoin. In the reverse reaction, catalyzes the NADP-dependent oxidation of 3alpha-hydroxysteroids and alcohol, but with much lower efficiency. Involved in the metabolism of 3alpha-hydroxysteroids, retinoid, isatin and xenobiotic carbonyl compounds. a secondary alcohol + NADP(+) = a ketone + H(+) + NADPH 3alpha-hydroxy-5beta-pregnan-20-one + NADP(+) = 5beta-pregnan-3,20-dione + H(+) + NADPH 5beta-dihydrotestosterone + H(+) + NADPH = 5beta-androstane-3alpha,17beta-diol + NADP(+) all-trans-retinol + NADP(+) = all-trans-retinal + H(+) + NADPH H(+) + isatin + NADPH = 3-hydroxyindolin-2-one + NADP(+) Homotetramer. The C-terminus peroxisomal targeting signal tripeptide is important for peroxisomal import. Once in the peroxisome, it is involved in intersubunit interactions. Three specific residues, Phe-177, Leu-180 and Asn-196 are conserved between non-primate mammals whereas the respective residues are serine, phenylalanine and threonine in primates. The two residues at positions 177 and 180 are molecular determinants responsible for the stereoselective reduction of 3-ketosteroids and benzil. The presence of an asparagine at position 196 is important for the maintenance of the quaternary structure resulting in stability at cold temperature and improved catalytic activity toward retinal. Primate DHRS4s display different stereoselectivity and catalytic efficiency in the oxidoreduction of some substrates as compared to other mammal DHRS4s due to a difference in conserved amino acid residues. Belongs to the short-chain dehydrogenases/reductases (SDR) family. Truncated N-terminus.