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Cholic Acid. Freshman Chemistry Jane Nguyen April 25, 2001. Breakdown of the Major Class of Organic Compounds Known as Lipids. 4 major classes of organic compounds found in cells: carbs, lipids, proteins, nucleic acids
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Cholic Acid Freshman Chemistry Jane Nguyen April 25, 2001 Jane Nguyen
Breakdown of the Major Class of Organic Compounds Known as Lipids • 4 major classes of organic compounds found in cells: carbs, lipids, proteins, nucleic acids • Lipids – only class that does not consist of polymers; grouped together due to one trait:little or no affinity for water • Steroids – class of lipids that have a characteristic fused carbon-ring structure • Bile Acids – one of the four groups of steroids • Cholic Acid – the primary human bile acid Jane Nguyen
Characteristic Structure of All Steroids Jane Nguyen
Structure of Cholic Acid • 3alpha,7alpha,12alpha-Trihydroxy-5beta-cholanate Cholate • Molecular Formula: C24H40O5 Jane Nguyen
Conformation & Configuration • Cyclohexane rings are quite stable; sp3 hybrid orbitals on adjacent C atoms overlap head-on • The six C atoms of the cyclohexane ring can exist in either the chair, boat, or twist form. • The Chair form is usually preferred Jane Nguyen
Bile and Bile Acids • An important fluid produced by the liver that contains water, electrolytes, and organic molecules including bile acids (like cholic acid) • Bile acids maintain cholesterol homeostasis • Are crucial for digestion and absorption of fats and fat-soluble vitamins • 400-800mL produced daily Jane Nguyen
Production, Storage, Transport of Cholic Acid • Produced from cholesterol in the liver; 500mg cholesterol converted to bile acids daily • Conjugated to an amino acid (taurine or glycine) • Collected in biliary passages • Stored in the gallbladder • Secreted into the duodenum Jane Nguyen
Conjugate Form • Amphipathic • Portion derived from cholesterol (cholic acid itself) is hydrophobic • Amino acid portion is hydropphilic Jane Nguyen
Roles • Aids in digestion of fats ( through emulsification) • Important in limiting cholesterol in the body • Absorbs fat-soluble vitamins such as vitamins A, D, E, and K • Antibacterial activity Jane Nguyen
Recent Findings • Bile acids also function as hormones that bind to nuclear receptors • These bile acid-receptor complexes bind to promoter regions of specific genes to stimulate or suppress their transcription • Bile acids are recycled by absorption in the ileum Jane Nguyen
THE END Jane Nguyen