Lipoprotein

In medicine and biochemistry, lipoproteins are "lipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are spherical particles consisting of a hydrophobic core of triglycerides and cholesterol esters surrounded by a layer of hydrophilic free cholesterol; phospholipids; and apolipoproteins. Lipoproteins are classified by their varying buoyant density and sizes. The large lipoproteins (chylomicrons; VLDL) are to transport triglycerides, and the small lipoproteins (LDL; HDL) are to transport cholesterol."

Classification
Lipoproteins that are normally present.
 * HDL lipoproteins (alpha lipoproteins) contain HDL cholesterol. Low levels are found in the familial disorders hypoalphalipoproteinemias.
 * IDL lipoproteins
 * LDL lipoproteins (beta lipoproteins) contain LDL cholesterol.
 * Lipoprotein(a)
 * VLDL lipoproteins (prebeta lipoproteins) contain VLDL cholesterol. High levels are found in the familial disorder hyperlipoproteinemia type IIB.
 * Chylomicrons

Abnormal lipoproteins not normally present.
 * Lipoprotein-X