Structure and Dynamics of Human Plasma Lipoproteins

Fatty acids have three distinct and important metabolic roles in animals. The fatty acyl moieties of phospholipids are the components of cellular membranes that provide the hydrophobic barriers between individual intra- and extracellular aqueous compartments. This structural role of fatty acids is the basis of cellular integrity. In addition, the degradation of fatty acyl chains is a highly efficient mechanism for the generation of metabolic energy. Moreover, fatty acids are precursors for prostacyclin, thromboxane, and leucotrienes, all of which are highly potent cellular effectors. Some of the cellular demand for phospholipid fatty acids for membrane synthesis can be met by intracellular synthesis. Most of the fatty acids needed for energy metabolism and all of the essential fatty acids for autocoid synthesis must be supplied exogeneously. Plasma lipoproteins are the vehicles for transport of these water insoluble lipids in the circulation. Lipoproteins also function as circulating reservoirs for the lipid soluble vitamins and environmentally derived contaminants, such as pesticides and polynuclear aromatic hydrocarbons (Smith et al., 1982b).