Alcohol dehydrogenase

Alcohol dehydrogenase

Structure of Alcohol Dehydrogenase

Alcohol dehydrogenase (ADH) is a group of enzymes that catalyze the conversion of alcohols to aldehydes or ketones with the reduction of NAD+ to NADH. These enzymes play a crucial role in the metabolism of alcohols in various organisms, including humans.

Structure

Alcohol dehydrogenases are typically dimeric or tetrameric enzymes, with each subunit containing a zinc ion that is essential for their catalytic activity. The zinc ion is coordinated by cysteine residues, as shown in the image

Zinc interaction with cysteine residues

.

Function

The primary function of alcohol dehydrogenase is to facilitate the oxidation of alcohols to aldehydes or ketones. This reaction is important in the metabolism of ethanol in the liver, where ethanol is converted to acetaldehyde, a process that is crucial for the detoxification of alcohol in the body.

Types

There are several classes of alcohol dehydrogenases, each with different substrate specificities and tissue distributions. In humans, the most well-known is the class I alcohol dehydrogenase, which is primarily found in the liver.

Mechanism

The catalytic mechanism of alcohol dehydrogenase involves the transfer of a hydride ion from the alcohol to the NAD+ cofactor, forming NADH. The active site of the enzyme, depicted in

Active site of Alcohol Dehydrogenase

, is where this reaction takes place.

Clinical significance

Mutations or polymorphisms in alcohol dehydrogenase genes can affect an individual's ability to metabolize alcohol, influencing susceptibility to alcoholism and alcohol-related liver disease.

Related pages

• Enzyme
• Metabolism
• Ethanol
• NAD+

Gallery

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  Liver alcohol dehydrogenase
• 
  Alcohol dehydrogenase structure
• 
  Crystal structure of alcohol dehydrogenase