Retinoids dehydrogenase/reductase with a clear preference for NADP. Displays high activity towards 9-cis, 11-cis and all-trans-retinal. Shows very weak activity towards 13-cis-retinol (PubMed:15865448, PubMed:12226107). Also exhibits activity, albeit with lower affinity than for retinaldehydes, towards lipid peroxidation products (C9 aldehydes) such as 4-hydroxynonenal and trans-2-nonenal (PubMed:19686838, PubMed:15865448). May play an important function in photoreceptor cells to detoxify 4-hydroxynonenal and potentially other toxic aldehyde products resulting from lipid peroxidation (PubMed:19686838). Has no dehydrogenase activity towards steroids (PubMed:15865448, PubMed:12226107). all-trans-retinol + NADP(+) = all-trans-retinal + H(+) + NADPH 11-cis-retinol + NADP(+) = 11-cis-retinal + H(+) + NADPH 9-cis-retinol + NADP(+) = 9-cis-retinal + H(+) + NADPH a 4-hydroxynonen-1-ol + NADP(+) = a 4-hydroxynonenal + H(+) + NADPH (E)-non-2-en-1-ol + NADP(+) = (E)-non-2-enal + H(+) + NADPH (Z)-non-6-en-1-ol + NADP(+) = (Z)-non-6-enal + H(+) + NADPH NADP(+) + nonan-1-ol = H(+) + NADPH + nonanal kcat is 36 min(-1) for all-trans-retinal as substrate. kcat is 45 min(-1) for 11-cis-retinal as substrate. kcat is 14 min(-1) for 9-cis-retinal as substrate. kcat is 27 min(-1) for all-trans-retinol as substrate. kcat is 7 min(-1) for 11-cis-retinol as substrate. kcat is 7 min(-1) for 9-cis-retinol as substrate. kcat is 56 min(-1) for nonanal as substrate. kcat is 45 min(-1) for (Z)-non-6-enal as substrate. kcat is 28 min(-1) for (E)-non-2-enal. Cofactor metabolism; retinol metabolism. Widely expressed, mostly in retina, kidney, brain, skeletal muscle, pancreas and stomach. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Shows clear specificity for the pro-S hydrogen on C4 of NADPH and the pro-R hydrogen on C15 of retinols. Belongs to the short-chain dehydrogenases/reductases (SDR) family.