ABSTRACT
Structure and function Triacylglycerols (Section K4), phospholipids (Section E1) and cholesterol (Section K5) are relatively insoluble in aqueous solution. Hence, they are transported around the body in the blood as components of lipoproteins. These globular, micelle-like particles consist of a hydrophobic core of triacylglycerols and cholesterol esters surrounded by an amphipathic coat of protein, phospholipid and cholesterol. The protein components of lipoproteins are called apolipoproteins (or apoproteins). At least 10 different apoproteins are found in the different human lipoproteins. Their functions are to help solubilize the hydrophobic lipids and to act as cellular targeting signals. Lipoproteins are classified into five groups on the basis of their physical and functional properties (Table 1).
