Purification and characterization of a cholesterol-binding protein from human pancreas.
The protein composition of human intestinal lavage fluids was analysed by electroimmunoassay. In addition to secretory immunoglobulin A and other components that were antigenically related to serum proteins, a number of gut-specific proteins were detected. One of these was found to exhibit the capacity of binding sodium deoxycholate and cholesterol. After isolation of this cholesterol-binding protein from intestinal fluids, immunohistochemical studies utilizing a specific antiserum indicated the pancreas to be the organ of its synthesis. The protein was subsequently purified from necrobiotic pancreas tissues and was found to be composed of a single polypeptide chain with a mol. wt. of 28 000 and an isoelectric point of pH4.9. The deoxycholate binding capacity determined by gel chromatography in the presence of [3H]deoxycholate was calculated to be approx. 24 mol of deoxycholate/mol of protein. In the intestinal fluids the protein appeared to be present in firm association with cholesterol, phospholipids, triacylglycerols and bile salts as a macromolecular protein-lipid complex. The possibility is raised that the pancreas-derived, cholesterol-binding protein may fulfil a function as an intestinal 'lipoprotein'.
D000596:Amino Acids / Q000032:analysis; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D003840:Deoxycholic Acid / Q000378:metabolism; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007413:Intestinal Mucosa / Q000378:metabolism; D010179:Pancreas / Q000378:metabolism*; D010196:Pancreatic Elastase
D000596:Amino Acids; D002352:Carrier Proteins; D003840:Deoxycholic Acid; D010196:Pancreatic Elastase; C017130:cholesterol-binding protein