Oxidizes medium and long chain aldehydes into non-toxic fatty acids. an aldehyde + H2O + NAD(+) = a carboxylate + 2 H(+) + NADH 2 H(+) + hexadecanoate + NADH = H2O + hexadecanal + NAD(+) H2O + NAD(+) + octanal = 2 H(+) + NADH + octanoate Alcohol metabolism; ethanol degradation; acetate from ethanol: step 2/2. Expressed in testis, white adipose tissue, lung, small intestine, kidney, spleen and liver. Geranylgeranylation is important for localization to lipid droplets and enzyme activity. Belongs to the aldehyde dehydrogenase family.