Histidine-rich glycoprotein is an abundant plasma glycoprotein that is involved in diverse biological processes, including angiogenesis, hemostasis, cell adhesion, and immunity.1,2 It is composed of a signal peptide and two cystatin-like regions in the N-terminal domain, a central domain with a histidine-rich region (HRR) and two proline-rich regions (PRRs) on either side, and a C-terminal domain. Histidine-rich glycoprotein is mainly produced by the liver but is also found in platelets and megakaryocytes.3,4 It has many binding partners, including IgG, immunoglobulin γ receptor (FcγR), and complement 1q (C1q), which bind to the N-terminal domain, zinc, heme, and microbes, which bind to the HRR, heparin and heparan sulfate, which bind to the N-terminal domain and HRR, plasminogen and thrombospondin, which bind to the N-terminal and C-terminal domains, and phospholipids, fibrinogen, and complement components, which have undefined binding regions.2 Histidine-rich glycoprotein is also able to bind to various cell types such as T cells, B cells, erythrocytes, endothelial cells, and several cancer types. It modulates macrophage polarization, facilitates the clearance of apoptotic and necrotic cells, promotes antitumor immunity, and has antibacterial and antiviral activities.1,2 Overexpression of HRG decreases tumor burden, metastasis, hypoxia, and blood vessel density and increases tumor-associated macrophage (TAM) accumulation in several mouse xenograft models.5 Increased plasma levels of histidine-rich glycoprotein are associated with the development of post-thrombotic syndrome following a venous thromboembolic event (VTE).6 Cayman's Histidine-rich Glycoprotein (human, recombinant) protein can be used for cell-based adhesion assays. This protein consists of 518 amino acids, has a calculated molecular weight of 59 kDa, and a predicted N-terminus of Val19 after signal peptide cleavage. By SDS-PAGE, under reducing conditions, the apparent molecular mass of the protein is 75-80 kDa due to glycosylation.WARNING This product is not for human or veterinary use.
