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Two 7 alpha-hydroxylase enzymes in bile acid biosynthesis
M Schwarz1, E G Lund, D W Russell
1Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235-9046, USA.
Current Opinion in Lipidology
|April 29, 1998
Summary
The synthesis of bile acids involves a crucial early step catalyzed by two cytochrome P450 enzymes. Researchers have identified the genes for these enzymes, revealing two conserved pathways for producing 7 alpha-hydroxylated bile acids.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Bile acid synthesis is essential for digestion and metabolism.
- The initial 7-hydroxylation step is critical and often rate-limiting.
- Cytochrome P450 enzymes play a key role in this hydroxylation process.
Purpose of the Study:
- To identify and characterize the enzymes responsible for 7-hydroxylation in bile acid synthesis.
- To elucidate the genetic pathways involved in producing 7 alpha-hydroxylated bile acids.
Main Methods:
- Isolation of cDNAs encoding cholesterol 7 alpha-hydroxylase and oxysterol 7 alpha-hydroxylase.
- Analysis of evolutionary conservation of the identified genes and pathways.
Main Results:
- Two specific cytochrome P450 enzymes, cholesterol 7 alpha-hydroxylase and oxysterol 7 alpha-hydroxylase, were identified as catalysts for the 7-hydroxylation step.
- The isolated cDNAs confirmed the existence of two evolutionarily conserved pathways for 7 alpha-hydroxylated bile acid production.
Conclusions:
- The identified enzymes and pathways provide a fundamental understanding of bile acid biosynthesis.
- This research offers insights into potential targets for metabolic and liver disease therapies.