HRG/HPRG Protein, Human, Recombinant (His Tag)

Histidine-rich glycoprotein, also known as HRG and HPRG, is a glycoprotein located in plasma and platelets and contains an unusually large amount of histidine and proline. In humans, five distinct domains are recognized in the mature HPRG molecule. There are two N-terminal cystatin-like modules (aa 19 - 254) and one His-Pro-rich region (aa 350 - 497) that is flanked by two Pro-rich segments (aa 276 - 321 and 498 - 525) . The His-Pro-rich region contains 10 tandem repeats with an HHPHG motif, and the N- and C-termini are linked by a disulfide bond. The specific functions of HRG remain unclear, but it is known that the protein binds heme, dyes, and divalent metal ions. It inhibits rosette formation and interacts with heparin, thrombospondin, and plasminogen. Two of the protein's effects, the inhibition of fibrinolysis, and the reduction of inhibition of coagulation indicate a potential prothrombotic effect. HPRG is evolutionarily, functionally, and structurally related to cleaved high molecular weight kininogen (HKa), an anti-angiogenic polypeptide that stimulates apoptosis of proliferating endothelial cells through binding to cell-surface tropomyosin. The antiangiogenic activity of the multidomain plasma protein HPRG is localized to its histidine-proline-rich (H/P) domain and has recently been shown to be mediated, at least partially, through binding to cell-surface tropomyosin in fibroblast growth factor-2-activated endothelial cells.

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) . Human HPRG immobilized at 1 μg/ml (100 μl/well) will induce >65% MOLT4 cell adhesion (1 x 10E5 cells/well) in the presence of 7.5 μg/ml Concanvalin A.

Lyophilized from sterile PBS, pH 7.4. Please contact us for any concerns or special requirements. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween 80 are added as protectants before lyophilization. Please refer to the specific buffer information in the hard copy of CoA.

The secreted recombinant human HPRG comprises 518 amino acids with a predicted molecular mass of 59 kDa. As a result of glycosylation, rhHPRG migrates as an approximately 75-80 kDa band in SDS-PAGE under reducing conditions.

In general, recombinant proteins are provided as lyophilized powder which are shipped at ambient temperature. Bulk packages of recombinant proteins are provided as frozen liquid. They are shipped out with blue ice unless customers require otherwise. Stable for 1 year at -20°C or below from date of shipment. For maximum recovery of product, centrifuge the original vial after thawing and opening the cap. For long-term storage, aliquot and store at -20°C or below. Avoid repeated freeze-thaw cycles.