Apolipoprotein, Recombinant, Human (A-I/ApoA1, Alp-1, APOA1, Brp-14, Ltw-1, Lvtw-1, Sep-1, Sep-2)

Apolipoprotein A1 (ApoA1) is a 28kD glycoprotein that is the major protein component of high density lipoprotein (HDL) particles. HDL particles play a central role in the reverse transport of cholesterol from peripheral tissues to the liver. HDL is known as �good cholesterol� due to its ability to facilitate the removal of cholesterol from macrophage foam cells in atherosclerotic plaques and thereby retard the progression of disease (1, 2). ApoA1 is secreted from hepatocytes with variable amounts of lipidation (3). Disc�like HDL particles increase in size and adopt a spherical shape as they are loaded with additional lipids and cholesterol by ABC family transporters (4, 5). HDL particle interaction with lipid�supplying cells is mediated by ApoA1 binding to the scavenger receptor SR-A1 (6). HDL particles are further modified by the circulating enzymes LCAT (which converts cholesterol to cholesteryl esters), CETP (which transfers cholesteryl esters to LDL/VLDL particles), and PLTP (which transfers phospholipids from HDL to LDL/VLDL particles) (2). Upon HDL particle return to the liver, ApoA1 binds to the scavenger receptor SR�B1 and the beta chain of ATP synthase on hepatocytes (7, 8). Hepatocytes internalize the particles and pass the cholesterol into bile for excretion. Polymorphisms of ApoA1 are associated with dysregulation of HDL levels and cholesterol homeostasis (1, 9). ApoA1 is catabolized in the kidney following its binding to Cubulin on renal proximal tubule epithelial cells (10). ApoA1, either as a free molecule or in lipidated particulate form, induces the release of insulin from pancreatic islets in a process that is dependent on ABCA1 and SR�B1 (11). Mature human ApoA1 shares 65% and 62% aa sequence identity with mouse and rat ApoA1, respectively. Source: Recombinant protein corresponding to aa25-267 from human Apolipoprotein, with N-terminal Met and 6-His tag, expressed in E. coli. Molecular Weight: ~27kD Endotoxin: <0.10 EU/ug Storage and Stability: Lyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Reconstituted product is stable for 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.