Acetaldehyde hydrate and carbonic anhydrase: possible roles in the inhibition of brain aldehyde dehydrogenase.

One biochemical explanation for the chronic and addictive effects of ethanol involves a relationship between biogenic aldehydes, brain aldehyde dehydrogenase and acetaldehyde, the principal metabolic product of ethanol. We suggest here the possibility that acetaldehyde hydrate may act as an especially strong inhibitor of aldehyde dehydrogenase. Aldehyde hydrates are known to strongly inhibit aldehyde dehydrogenase as well as a number of other aldehyde oxidizing enzymes and it may be that acetaldehyde hydrate acts as a transition state or activated intermediate inhibitor. It is also suggested that carbonic anhydrase, which catalyzes the very rapid equilibrium between acetaldehyde and its hydrate, may play a role in this process.