Cholestenol Delta-isomerase

Cholestenol Delta-isomerase

Cholestenol Delta-isomerase is an enzyme that plays a crucial role in the biosynthesis of cholesterol. It is also known as 3-beta-hydroxy-Delta-5-steroid dehydrogenase or 3-beta-hydroxy-Delta-5-C27-steroid oxidoreductase. This enzyme is encoded by the CHDH gene in humans.

Function

Cholestenol Delta-isomerase catalyzes the conversion of cholestenol to cholesterol, an essential component of cell membranes and a precursor for the synthesis of steroid hormones. This enzymatic reaction involves the isomerization of the double bond at the Delta-5 position of the steroid molecule.

Importance

The activity of Cholestenol Delta-isomerase is crucial for maintaining proper cholesterol levels in the body. Cholesterol is involved in various physiological processes, including cell membrane integrity, hormone synthesis, and bile acid production. Dysregulation of cholesterol metabolism can lead to various diseases, such as atherosclerosis and familial hypercholesterolemia.

Structure

Cholestenol Delta-isomerase is a membrane-bound enzyme found in the endoplasmic reticulum of cells. It consists of a single polypeptide chain with multiple transmembrane domains. The active site of the enzyme is located within the membrane, where the isomerization reaction takes place.

Regulation

The activity of Cholestenol Delta-isomerase is tightly regulated to maintain cholesterol homeostasis. Several factors, including hormonal signals and dietary cholesterol intake, can influence the expression and activity of this enzyme. Additionally, genetic variations in the CHDH gene can affect the function of Cholestenol Delta-isomerase and contribute to cholesterol-related disorders.

Clinical Significance

Mutations in the CHDH gene have been associated with a rare genetic disorder called cerebrotendinous xanthomatosis (CTX). CTX is characterized by the accumulation of cholestanol, a precursor of cholesterol, in various tissues. This leads to neurological symptoms, such as cognitive impairment and movement disorders. Treatment for CTX often involves cholesterol-lowering medications and dietary modifications.

References

1. Cholesterol 2. Steroid hormones 3. Atherosclerosis 4. Familial hypercholesterolemia 5. Endoplasmic reticulum 6. Cerebrotendinous xanthomatosis