Lipoprotein, low density from human plasma, >=95% (SDS-PAGE), solution

Synonyms: beta-Lipoprotein; LDL; Low density lipoprotein

MDL No.: MFCD00131524

Purity: >=95% (SDS-PAGE)

Storage: 2-8C

UNSPSC Code: 12352211

Biochem/physiol Actions: LDL and HDL transport both dietary and endogenous cholesterol in the plasma. LDL is the main transporter of cholesterol and cholesteryl esters and makes up more than half of the total lipoprotein in plasma. LDL is absorbed by the liver and other tissues via receptor mediated endocytosis. The cytoplasmic domain of the LDL receptor facilitates the formation of coated pits; receptor-rich regions of the membrane. The ligand binding domain of the receptor recognizes apo-B100 on LDL, resulting in the formation of a clathrin-coated vesicle. ATP-dependent proton pumps lower the pH inside the vesicle resulting dissociation of LDL from its receptor. After loss of the clathrin coat the vesicles fuse with lysozomes, resulting in peptide and cholesteryl ester enzymatic hydrolysis. The LDL receptor can be recycled to the cell membrane. Insulin, tri-iodothyronine and dexamethasome have shown to be involved with the regulation of LDL receptor mediated uptake.

Physical form: Solution in 150 mM NaCl and 0.01% EDTA, pH 7.4

Physical properties: Low density lipoproteins are smaller than VLDL and IDL (26 nm) (MW approximately 3.5 million) and more dense (~1.04). The protein component of LDL is apolipoprotein B100. LDL contains 20-22% protein, 10-15% triglycerides, 20-28% phospholipids, 37-48% cholesteryl esters and 8-10% cholesterol.

Other Notes: View more information on lipoprotein function and lipid transport at www.sigma-aldrich.com/enzymeexplorer