Oxidizes medium and long chain saturated and unsaturated aldehydes. Metabolizes also benzaldehyde. Low activity towards acetaldehyde and 3,4-dihydroxyphenylacetaldehyde. May not metabolize short chain aldehydes. Can use both NADP(+) and NAD(+) as electron acceptor. May have a protective role against the cytotoxicity induced by lipid peroxidation. an aldehyde + H2O + NADP(+) = a carboxylate + 2 H(+) + NADPH an aldehyde + H2O + NAD(+) = a carboxylate + 2 H(+) + NADH 2 H(+) + hexadecanoate + NADH = H2O + hexadecanal + NAD(+) H2O + NAD(+) + octanal = 2 H(+) + NADH + octanoate H2O + NADP(+) + octanal = 2 H(+) + NADPH + octanoate benzaldehyde + H2O + NADP(+) = benzoate + 2 H(+) + NADPH benzaldehyde + H2O + NAD(+) = benzoate + 2 H(+) + NADH H2O + hexanal + NADP(+) = 2 H(+) + hexanoate + NADPH (E)-4-hydroxynon-2-enal + H2O + NADP(+) = (E)-4-hydroxynon-2-enoate + 2 H(+) + NADPH (2E)-octenal + H2O + NADP(+) = (2E)-octenoate + 2 H(+) + NADPH (2E)-octenal + H2O + NAD(+) = (2E)-octenoate + 2 H(+) + NADH Alcohol metabolism; ethanol degradation; acetate from ethanol: step 2/2. Primarily in the plasma membrane as well as in some punctate structures in the cytoplasm. Dually lipidated in the C-terminus; prenylation occurs prior to, and is a prerequisite for palmitoylation. It is also required for activity towards long-chain substrates. Belongs to the aldehyde dehydrogenase family.