• Purity

  >90%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

  <0.01 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to support the adhesion of MOLT?4 human acute lymphoblastic leukemia cells. Lamb-Wharton, R.J. and W.T. Morgen (1993) Cell Immunol.     152:544. When 1 x 10    ⁵ cells/well are added to Recombinant Mouse HPRG coated plates, adhesion is induced in a dose-dependent manner in the presence of Concanvalin A. The ED    ₅₀ for this effect is 0.6-3 μg/mL.

• Source

  Mouse myeloma cell line, NS0-derived Leu19-Lys525, with a C-terminal 10-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Leu19

• Predicted Molecular Mass

  58.5 kDa

• SDS-PAGE

  80-85 kDa, reducing conditions

Background: HPRG

Mouse histidine-rich glycoprotein (HPRG) is a multidomain, monomeric, secreted, 67 - 75 kDa member of the cystatin superfamily of molecules (1, 2). Its name derives from the fact that 22% of its amino acids (aa) are histidine and proline. In mouse, it is synthesized as a 525 amino acid (aa) precursor that contains an 18 aa signal sequence and a 507 aa mature region (3). Five distinct domains are recognized in the mature molecule. There are two N-terminal cystatin-like modules and one His-Pro-rich region that is flanked by two Pro-rich segments (3, 4). The His-Pro-rich region contains multiple tandem repeats with a GHHPH motif, while the N- and C-termini are linked by a disulfide bond (3, 5, 6). Mouse HPRG is only 60% aa identical to human HPRG, and 79% aa identical to rat HPRG. There are multiple ligands for HPRG. These include small molecular weight molecules (metal ions; heme), hemostatic molecules (heparan sulfate; TSP; plasminogen), and immune system components (T cells; macrophages) (1, 5). About 50% of plasma plasminogen circulates bound to HPRG. Upon immobilization to cell surface tropomyosin in a Zn⁺⁺?dependent manner, it is converted to plasmin by tPA (7 - 9). HPRG also shows antiangiogenic activity on endothelial cells (10). Finally, it binds to cytoplasmic ligand(s) exposed during cellular necrosis, and facilitates macrophage phagocytosis (11).

• References:

1. Jones, A.L. et al. (2005) Immunol. Cell Biol. 83:106.

2. Koide, T. and S. Odani (1987) FEBS Lett. 216:17.

3. Hulett, M.D. and C.R. Parish (2000) Immunol. Cell Biol. 78:280.

4. GenBank Accession # NP_444406.

5. Borza, D-B. et al. (1996) Biochemistry 35:1925.

6. Sorensen, C.B. et al. (1993) FEBS Lett. 328:285.

7. Donate, F. et al. (2004) Cancer Res. 64:5812.

8. Borza, D-B. and W.T. Morgan (1997) J. Biol. Chem. 272:5718.

9. Guan, X. et al. (2004) Thromb. Haemost. 92:403.

10. Juarez, J.C. et al. (2002) Cancer Res. 62:5344.

11. Jones, A.L. et al. (2005) J. Biol. Chem. 280:35733.

• Long Name:

  Histidine-rich Glycoprotein Precusor

• Entrez Gene IDs:

  3273 (Human)

• Alternate Names:

  DKFZp779H1622; Histidine-proline-rich glycoprotein; histidine-rich glycoprotein; HPRG; HPRGHRGP; HRG