Micelle formation by bile salts. Physical-chemical and thermodynamic considerations
Carey, M.C.; Small, D.M.
Archives of Internal Medicine 130(4): 506-527
1972
ISSN/ISBN: 0003-9926 PMID: 4562149 Document Number: 51128
Bile salts, which are soluble amphiphiles, possess a unique molecular structure when compared with typical detergent molecules. In water, bile salts form micelles. The behaviour of these micelles is quite different from those formed by detergents. Bile salts micelles are smaller, more highly charged than detergent micelles and of different structure. Bile salts form mixed micelles with a variety other soluble and insoluble lipids. While bile salts increase slightly the solubility of relatively nonpolar molecules (such as cholesterol or fatty acids), they have a striking capacity to solubilise insoluble molecules of biological importance such as phospholipids and monoglycerides; as little as 1 mole of bile salt can solubilise 2 moles of lecithin. Solubilisation takes place in mixed bile salt micelles of unique structure and properties. These mixed micelles incorporate appreciable amounts of insoluble molecules, such as fat-soluble vitamins and cholesterol, and thus solubilise them in such fluids as bile and intestinal luminal content.