Lipoproteins are round particles made of fat (lipids) and proteins that travel in the bloodstream to cells throughout your body. Cholesterol and triglycerides are two types of lipids found in lipoproteins. The body makes different types of lipoproteins. High levels of certain lipoproteins can be harmful to your heart. Apolipoproteins have four major functions including 1) serving a structural role, 2) acting as ligands for lipoprotein receptors, 3) guiding the formation of lipoproteins, and 4) serving as activators or inhibitors of enzymes involved in the metabolism of lipoproteins.
