Apolipoprotein H, Recombinant, Human (beta 2 Glycoprotein 1, ApoHb2gp1)

Apolipoprotein H (ApoH), also known as B2-Glycoprotein I/B2-GPI, is a 50kD variably glycosylated member of the complement control superfamily of proteins (1, 2). Mature mouse ApoH consists of four tandem Sushi/SCR repeats followed by one Sushi-like repeat (3, 4). Mature mouse ApoH shares 76-42aa sequence identity with human and rat ApoH, respectively. Hepatocyte- derived ApoH binds directly to negatively charged phospholipids (5). It circulates as a component of lipoprotein particles and as a lipid-free serum protein (6). ApoH also associates with liposomes and apoptotic cell debris, thereby enabling their renal clearance via Megalin uptake (7, 8). Circulating levels of ApoH are postively correlated with triglyceride-rich lipoprotein (VLDL) components in type II diabetes (9). ApoH inhibits thrombosis by blocking the activation of Coagulation Factor XI but also shows procoagulant activity by inhibiting the activation of Protein C (10, 11). ApoH can be cleaved by Plasmin at Lys317 - Thr318, an action that is enhanced by heparin (12, 13). ApoH cleavage reduces its ability to bind phospholipids and inhibit Factor XI activation but confers the ability to bind Plasminogen (10, 12, 14). Cleaved ApoH also demonstrates antiangiogenic activity, whereas intact ApoH does not (14). The production of antibodies against ApoH is a hallmark of Antiphospholipid Syndrome (APS), an autoimmune disorder that leads to hypercoagulability and recurrent miscarriages (15). ApoH binds to the surface antigen of Hepatitis B Virus and is associated with the development of HBV-induced hepatocellular carcinoma (6, 16).\n\nSource:\nRecombinant corresponding to aa20-345 from mouse Apolipoprotein H, fused with 6-His tag, expressed in NS0 cells.\n\nMolecular Weight: \n~39.2kD\n\nEndotoxin Level:\n(same/less than)1EU/1ug (LAL)\n\nBiological Activity:\nMeasured by its binding ability in a functional ELISA. When recombinant mouse Apolipoprotein H/ApoH is immobilized at 2ug/ml, 100ul/well, the concentration of recombinant mouse LDL R that produces 50% of the optimal binding response is found to be ~0.05-0.25ug/ml.\n\nStorage and Stability:\nLyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with PBS. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Reconstituted product is stable for 6 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.

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SPECIFICATIONS

Catalog Number

A2299-77S

Size

50ug

Form

Supplied as a lyophilized powder in PBS. Reconstitute with PBS to 500ug/ml.

Purity

~95% (SDS-PAGE)

References

1.Crook, M.A. et al. (2010) Atherosclerosis 209:32. 2. Miyakis, S. et al. (2004) Thromb. Res. 114:335. 3. Nonaka, M. et al. (1992) Genomics 13:1082. 4. Lozier, J. et al. (1984) Proc. Natl. Acad. Sci. 81:3640. 5. Wurm, H. (1984) Int. J. Biochem. 16:511. 6. Mehdi, H. et al. (1994) J. Virol. 68:2415. 7. Chonn, A. et al. (1995) J. Biol. Chem. 270:25845. 8. Moestrup, S.K. et al. (1998) J. Clin. Invest. 102:902. 9. Castro, A. et al. (2010) Atherosclerosis 209:201. 10. Shi, T. et al. (2004) Proc. Natl. Acad. Sci. 101:3939. 11. Mori, T. et al. (1996) Thromb. Haemost. 75:49. 12. Hunt, J. et al. (1993) Proc. Natl. Acad. Sci. 90:2141. 13. Guerin, J. et al. (2002) J. Biol. Chem. 277:2644. 14. Sakai, T. et al. (2007) Am. J. Pathol. 171:1659. 15. Adams, M. (2008) Semin. Thromb. Haemost. 34:251. 16. Jing, X. et al. (2010) J. Cancer Res. Clin. Oncol. 16:1671.