Steroid hydroxylase

Steroid hydroxylase is a type of enzyme that plays a crucial role in the metabolism of steroids. It is responsible for the hydroxylation of steroids, a chemical process that introduces a hydroxyl group (-OH) into the steroid molecule. This process is essential for the biological activity of steroids, as it allows them to be converted into their active forms.

Function

Steroid hydroxylase enzymes are involved in the biosynthesis of corticosteroids, glucocorticoids, mineralocorticoids, and sex steroids. They catalyze the addition of a hydroxyl group to specific carbon atoms in the steroid molecule. This hydroxylation process is a key step in the activation of steroids, as it enables them to bind to their respective steroid receptors and exert their biological effects.

Types

There are several types of steroid hydroxylase enzymes, each of which hydroxylates a specific position on the steroid molecule. These include:

• 17α-hydroxylase: This enzyme is involved in the biosynthesis of glucocorticoids and sex steroids. It hydroxylates the 17th carbon atom of the steroid molecule.
• 21-hydroxylase: This enzyme is crucial for the production of mineralocorticoids and glucocorticoids. It hydroxylates the 21st carbon atom of the steroid molecule.
• 11β-hydroxylase: This enzyme is involved in the final steps of corticosteroid synthesis. It hydroxylates the 11th carbon atom of the steroid molecule.

Clinical significance

Deficiencies in steroid hydroxylase enzymes can lead to various medical conditions. For example, a deficiency in 21-hydroxylase can cause congenital adrenal hyperplasia, a group of inherited disorders that affect the adrenal glands. Similarly, a deficiency in 11β-hydroxylase can lead to a form of congenital adrenal hyperplasia characterized by hypertension and virilization.

See also

• Hydroxylation
• Steroidogenesis
• Cytochrome P450