Aldehyde dehydrogenases

Dehydrogenases of subclass EC 1.2 that oxidise aldehydes to the corresponding carboxylic acids, usually with NAD+ or NADP+ as the electron acceptor. The human ALDH2 variant that clears acetaldehyde during alcohol metabolism is the famous family member: about a third of East Asians carry a deficient form, causing the alcohol flush reaction and raising cancer risk from drinking. In food analysis these enzymes enable specific assays for aldehyde levels in beverages, and in flavour chemistry their activity helps set aldehyde concentrations in fermented products — quiet enzymes with loud physiological consequences.