Apolipoprotein A-II, Human (Apo A-II), Highly Purified

High Density Lipoprotein (HDL) isolated by sequential isopycnic ultracentrifugation are delipidated. Apo A-II is purified by column chromatography in 6M urea (Schonfeld et al. 1977). Purity is determined by quantitative densitometry of SDS polyacrylamide gels (Laemlli 1970). Protein is determined by the Pierce BCA method (which was found to be comparable to the Lowry method) with 1% BSA as the standard. Apo A-II, which is a dimer composed of identical subunits, has a Mr of 17 kD and a pI of 4.9. Apo-II activates hepatic lipase and inhibits LCAT. Apolipoproteins are soluble in aqueous solutions. However, due to its amphipathic structure Apo-II self-associates into oligomers at high protein concentrations. Apo A-II exists as dimers in buffers with 5M guanidine-HCL or 6M urea. Source: Normal human plasma, fresh, non-frozen. Tested negative for HIV-1, HIV-2, HCV and HBc antibodies and HBsAg. Molecular Weight: 17,400, Storage and Stability: May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 6 months after receipt at -20°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.