Aldehyde reductase

Aldehyde Reductase is an enzyme that catalyzes the chemical reaction of reducing an aldehyde or ketone to a primary or secondary alcohol, respectively. This enzyme is part of the alcohol dehydrogenase family and is primarily found in the cytoplasm of cells.

Function

Aldehyde Reductase plays a crucial role in the metabolism of glucose and lipids. It is involved in the polyol pathway, a two-step process that converts glucose to fructose. In the first step, glucose is reduced to sorbitol by the enzyme aldose reductase. In the second step, sorbitol is oxidized to fructose by sorbitol dehydrogenase.

In addition to its role in glucose metabolism, aldehyde reductase also detoxifies a variety of aldehydes and their derivatives, including 4-hydroxynonenal, a toxic byproduct of lipid peroxidation.

Structure

The structure of aldehyde reductase is similar to that of other members of the alcohol dehydrogenase family. It is a monomer with a single polypeptide chain, and it contains a zinc atom that is essential for its catalytic activity. The enzyme also contains a NADPH binding site, which is involved in the reduction of aldehydes and ketones.

Clinical significance

Abnormal activity of aldehyde reductase has been implicated in several diseases, including diabetic complications, cataracts, and cancer. In particular, increased activity of this enzyme in people with diabetes can lead to an accumulation of sorbitol, which can cause osmotic stress and damage to tissues such as the retina and kidney.

See also

• Aldose reductase
• Alcohol dehydrogenase
• Polyol pathway
• 4-Hydroxynonenal