Final answer:
Alcohol dehydrogenase catalyzes the oxidation of ethanol to acetaldehyde.
Step-by-step explanation:
Alcohol dehydrogenase catalyzes the oxidation of ethanol to acetaldehyde. This enzyme is responsible for breaking down the majority of ethanol in the liver. The reaction involves the transfer of a hydrogen atom from ethanol to the coenzyme NAD+, producing acetaldehyde and NADH as products.