Histidine-proline-rich glycoprotein (HPRG), a member of the Cystatin structural superfamily, is an abundantly secreted multi-domain glycoprotein. Although the physiological function is largely unknown, HPRG potentially regulates physiological processes such as cell adhesion and migration, fibrinolysis, coagulation, complement activation, immune complex clearance and phagocytosis of apoptotic cells. HPRG can exert anti-angiogneic activity by stimulating apoptosis of endothelial cells. Recombinant Human HPRG is a 57.7 kDa glycoprotein containing 507 amino acid residues.