Ligand Information and Courses from MediaLab, Inc.

Lipoproteins differ in size and density as well as in their content (what they tend to carry). They also can differ in their origination (where they are made). Another significant difference between lipoprotein molecules is the proteins they have on their surfaces. These proteins, known as apolipoproteins, are the major identifying characteristics of a lipoprotein. There are many different apolipoproteins and we are continually learning more about them. Apolipoproteins have multiple roles. One role is that these amphipathic (detergent-like) proteins increase the overall solubility of the lipid particle, helping it to dissolve in the aqueous environment of the blood. Apolipoproteins can also function as enzyme co-factors (receptor ligands) and facilitate the transfer of their lipid cargo to specific cells. Thus, the apoliproteins are the smart or working-end of the lipoprotein particle. The apolipoproteins dictate where the particles will dock and where they can bind, and in so doing the apolipoproteins regulate lipid metabolism in the body.