Oxidized HDL Assay Kit (CML-HDL, Human) (ab242309)

Lipoproteins are submicroscopic particles composed of lipid and protein held together by noncovalent forces. Their general structure is that of a putative spheroidal microemulsion formed from an outer layer of phospholipids, unesterified cholesterol, and proteins, with a core of neutral lipids, predominately cholesteryl esters and triacylglycerols (TAG). Low density lipoprotein (LDL) is the major transport protein for cholesterol in human plasma. LDL is a spherical particle with a diameter of 20-25 nm. Each LDL particle contains cholesteryl esters in its core which are surrounded by a hydrophilic coat composed of phospholipids, cholesterol, and one molecule of a hydrophobic protein known as apolipoprotein B-100. LDL cholesterol, sometimes referred to as “bad” cholesterol, is even more dangerous when it becomes oxidized. Oxidized LDL (OxLDL) is more reactive with surrounding tissues and can collect within the inner-lining of arteries. Macrophages, cholesterol, and other lipids can accumulate at the site (atherosclerosis), ultimately forming a plaque that can lead to heart attack, stroke or death. LDL oxidation affects both the protein and phospholipids of LDL. Reactive aldehyde products formed during the oxidation of polyunsaturated fatty acids, such as malondialdehyde (MDA) and 4hydroxynonenal (HNE), are capable of attaching covalently to the e-amino groups of lysine residues of of ApoB-100 to form MDA-Lys and HNE-Lys adducts (MDA-LDL and HNE-LDL). Advanced glycosylation, such as the formation of CML-LDL and CEL-LDL, are also involved in LDL oxidation.