LDL constitutes 50% of the total lipoprotein mass in plasma and is the major carrier of cholesterol and cholesteryl esters. LDL levels strongly correlate with coronary heart disease. Cholesterol is an important normal constituent of the body. It is part of the structure of cell membranes, bile acids and steroid hormones. Since cholesterol is water insoluble, most cholesterol is carried in the blood by lipoproteins. Lipoproteins are large protein-like molecules, including chylomicrons, VLDL, LDL and HDL. Chylomicrons are lipoproteins that are present shortly after a meal. They disappear within about 2 hours in "normal" people. The main function of LDL seems to be to carry cholesterol to various tissues throughout the body. LDL is sometimes referred to as "bad" cholesterol because elevated levels of LDL correlate most directly with coronary heart disease.||Storage and Stability:|May be stored at 4°C. For long-term storage, aliquot and store at 4°C. Do not freeze. Aliquots are stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial prior to removing the cap. Further dilutions can be made in assay buffer.