ALDHs play a major role in the detoxification of alcohol-derived acetaldehyde (Probable). They are involved in the metabolism of corticosteroids, biogenic amines, neurotransmitters, and lipid peroxidation (Probable). Oxidizes medium and long chain aldehydes into non-toxic fatty acids (PubMed:25286108). Preferentially oxidizes aromatic aldehyde substrates (PubMed:11784860). Comprises about 50 percent of corneal epithelial soluble proteins (PubMed:11784860). May play a role in preventing corneal damage caused by ultraviolet light (PubMed:10376761). an aldehyde + H2O + NAD(+) = a carboxylate + 2 H(+) + NADH H2O + NAD(+) + octanal = 2 H(+) + NADH + octanoate Homodimer. Constitutively expressed in cornea, stomach, skin, bladder and lungs. Lowest expression levels in lungs and bladder. There are two alleles, Ald3a1a and Ald3a1c. Ald3a1c codes for a low activity enzyme and is associated with extensive corneal clouding after exposure to ultraviolet light. Ald3a1a encodes the high activity enzyme. Belongs to the aldehyde dehydrogenase family.