Transcript Cholic Acid
Cholic Acid Freshman Chemistry Jane Nguyen April 25, 2001 25 April 2001 Jane Nguyen 1 Breakdown of the Major Class of Organic Compounds Known as Lipids 25 April 2001 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 Jane Nguyen Cholic Acid – the primary 2 Characteristic Structure of All Steroids 25 April 2001 Jane Nguyen 3 Structure of Cholic Acid 3alpha,7alpha,12alp ha-Trihydroxy5beta-cholanate Cholate Molecular Formula: C24H40O5 25 April 2001 Jane Nguyen 4 Conformation & Configuration 25 April 2001 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. Jane Nguyen The Chair form is 5 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 25 April 2001 Jane Nguyen 6 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 25 April 2001 Jane Nguyen 7 Conjugate Form Amphipathic Portion derived from cholesterol (cholic acid itself) is hydrophobic Amino acid portion is hydropphilic 25 April 2001 Jane Nguyen 8 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 25 April 2001 Jane Nguyen 9 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 25 April 2001 Jane Nguyen 10 THE END 25 April 2001 Jane Nguyen 11