Lipoprotein
A lipoprotein is a biochemical assembly that contains both proteins and lipids, bound to the proteins, which allow fats to move through the water inside and outside cells. The proteins serve to emulsify the lipid molecules. Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are lipoproteins. Examples include the plasma lipoprotein particles classified under high-density (HDL) and low-density (LDL) lipoproteins, which enable fats to be carried in the blood stream, the transmembrane proteins of the mitochondrion and the chloroplast, and bacterial lipoproteins.
Scope
Transmembrane lipoproteins
The lipids are often an essential part of the complex, even if they seem to have no catalytic activity by themselves. To isolate transmembrane lipoproteins from their associated biological membranes, detergents are often needed.
Plasma lipoprotein particles
The role of lipoprotein particles is to transport triacylglycerols (a.k.a. triglycerides) and cholesterol in the blood between all the tissues of the body. The most common being the liver and the adipocytes of adipose tissue. Particles are synthesized in the small intestine and the liver, but interestingly not in the adipocytes.