7-Dehydrositosterol

7-Dehydrositosterol is a sterol that is an intermediate in the biosynthesis of steroids. It is converted from fucosterol by the enzyme sterol C5-desaturase and is further converted to cholesta-5,7,24-trien-3β-ol by the enzyme sterol 24-reductase.

Biosynthesis

The biosynthesis of 7-dehydrositosterol involves several steps. The first step is the conversion of fucosterol to 7-dehydrositosterol by the enzyme sterol C5-desaturase. This enzyme removes two hydrogen atoms from the 5th carbon atom of the fucosterol molecule, creating a double bond and forming 7-dehydrositosterol.

The next step in the biosynthesis pathway is the conversion of 7-dehydrositosterol to cholesta-5,7,24-trien-3β-ol by the enzyme sterol 24-reductase. This enzyme reduces the 24th carbon atom of the 7-dehydrositosterol molecule, removing a double bond and forming cholesta-5,7,24-trien-3β-ol.

Role in Steroid Biosynthesis

7-Dehydrositosterol plays a crucial role in the biosynthesis of steroids. Steroids are essential for various biological functions, including the regulation of gene expression, the maintenance of cell membrane integrity, and the modulation of immune response.

See Also

• Sterol
• Biosynthesis
• Steroid
• Fucosterol
• Sterol C5-desaturase
• Sterol 24-reductase
• Cholesta-5,7,24-trien-3β-ol