Question: It is the accumulation of acetyaldehyde that results in the flushed face, dizziness, and light-headedness responses that are associated with ethanol intoxication. Interestingly there are multiple forms of the enzyme aldehyde dehydrogenase that are expressed by different people. Some isoforms have a very high Km for acetaldehyde, and these people are highly sensitive to the consumption of alcohol and will often show signs of intoxication after only a single drink. Can anyone explain this?