The function of ALDH1B1 (aldehyde dehydrogenase 1 family member B1, ENSG00000137124) is as follows. Broad specificity, mitochondrial aldehyde dehydrogenase that could play a role in the detoxification of alcohol-derived acetaldehyde and other aldehydes (PubMed:20616185, PubMed:25413692, PubMed:35788181). Shows an absolute preference for NAD(+) as no activity is detected with NADP(+) (PubMed:20616185, PubMed:25413692). Has a high affinity and catalytic efficiency toward aliphatic medium- chain saturated aldehydes relative to short-chain and aromatic aldehydes in vitro (PubMed:20616185). Also capable of metabolizing products of lipid peroxidation, namely 4-hydroxynon-2-enal(4-HNE) and malonaldehyde (MDA) but with lower catalytic efficiency (PubMed:20616185). In vitro, it can also display a nitroglycerin reductase activity (PubMed:25413692). Has also an esterase activity in vitro, but this may be not physiologically relevant in vivo (PubMed:20616185). {ECO:0000269|PubMed:20616185, ECO:0000269|PubMed:25413692, ECO:0000269|PubMed:35788181}.