Involved in oxidative stress tolerance by detoxifying reactive aldehydes derived from lipid peroxidation. Medium- to long-chain saturated aldehydes are preferred substrates, while the short-chain aldehyde propanal is a weak substrate. Can use both NAD(+) and NADP(+), but the coenzyme preference is substrate dependent. an aldehyde + H2O + NAD(+) = a carboxylate + 2 H(+) + NADH Thiol-based regulation. Inactivation after dimerization under oxidizing conditions. Optimum pH is 9.0. Homodimer and homomultimer. A number of isoforms are produced. According to EST sequences. By abscisic acid (ABA), dehydration, salt stress in plantlets. Induced by heavy metals and H(2)O(2). Plants overexpressing ALDH3I1 show improved tolerance when exposed to dehydration, salt stress, heavy metals and H(2)O(2). Belongs to the aldehyde dehydrogenase family.