The fatty, oily components of lipoproteins are not soluble in water. But because of their detergent-like (amphipathic) properties, apolipoproteins can dissolve them.
Apolipoproteins also serve as enzyme co-factors, receptor ligands, and lipid transfer carriers that regulate the metabolism of lipoproteins and their uptake in tissues.
Hundreds of genetic polymorphisms of the apolipoproteins have been described, and many of them alter their structure and function.
Apolipoprotein synthesis in the liver is controlled by a host of factors, including dietary composition, hormones (insulin, glucagon, thyroxin, estrogens, androgens), alcohol intake, and various drugs (statins, niacin,and fibric acids).