Sorbitol dehydrogenase

Sorbitol Dehydrogenase (SDH) is an enzyme that catalyzes the interconversion of sorbitol and fructose. It is a member of the alcohol dehydrogenase family and plays a significant role in the polyol pathway, a two-step process that converts glucose to fructose.

Function

SDH is primarily found in the liver, kidney, and spermatozoa, where it functions in the metabolism of sugar alcohols. It catalyzes the oxidation of sorbitol to fructose, a reaction that also involves the reduction of NAD+ to NADH. This reaction is reversible, and SDH can also catalyze the reduction of fructose to sorbitol.

Structure

SDH is a tetramer, with each subunit containing a zinc atom and a NAD+ binding site. The zinc atom is essential for the catalytic activity of the enzyme, while the NAD+ binding site is involved in the transfer of hydride ions during the reaction.

Clinical Significance

Alterations in SDH activity have been associated with various diseases, including diabetes, cataracts, and neuropathy. In diabetes, increased activity of the polyol pathway can lead to the accumulation of sorbitol, which can cause osmotic damage and contribute to the development of cataracts and neuropathy.

See Also

• Alcohol dehydrogenase
• Polyol pathway
• Diabetes
• Cataracts
• Neuropathy