BIOC 3300 Lecture 13: BIOC3300 Lecture 13
10 Mar 2017
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Document Summary
Lipoprotein structure: spherical complexes of lipids and proteins: uc, pl (mostly pc) and aplolipoprotein are on surface, tag and ce are sequestered in central core. Functions of the proteins include: structure of lipoprotein, cofactors for enzymes, ligands for receptors. Lipoproteins can be isolated according to density (centrifuge) or size (chromatography: electrophoresis will separate according to charge density. Major classes: chylomicrons: least dense, large diameter, large mass, lowest % protein, vldl, idl, ldl, hdl. Major species of human apolipoproteins: a-i: activates lcat (lecithin-cholesterol acyltransferase, b-48: cholesterol clearance, b-100: cholesterol clearance. Two broad classes of apolipoproteins based on their ability to exchange between lipoprotein particles. Exchangeability is related to the aqueous solubility of the protein. Apob proteins are non-exchangeable all remaining apolipoproteins are exchangeable. Exchangeable apolipoprotein structure is explained by the amphipathic -helix model: formed from multiple copies of 11 or 22 aa -helical repeats. The regulation of the synthesis of apolipoproteins and lipids is coordinated.
