Haptoglobin Human, Sf9

Haptoglobin is a glycoprotein primarily synthesized in the liver, although it is also produced by other tissues such as the skin, lungs, and kidneys . It plays a crucial role in binding free hemoglobin released during hemolysis, thereby preventing kidney injury and iron loss . The haptoglobin-hemoglobin complex is subsequently removed by the reticuloendothelial system, typically the spleen .

Haptoglobin consists of two alpha (A) and two beta (B) chains connected by disulfide bonds . There are three major phenotypes of haptoglobin: Hp 1-1, Hp 2-1, and Hp 2-2 . Among these, Hp 1-1 is the most effective in binding free hemoglobin and suppressing inflammatory responses, while Hp 2-2 is the least active . The molecular mass of haptoglobin ranges from 8 to 200 kDa .

Recombinant haptoglobin produced in Sf9 Baculovirus cells is a single, glycosylated polypeptide chain containing 338 amino acids and a molecular mass of 37.7 kDa . This recombinant form is fused to a 6 amino acid His Tag at the C-terminus .

Haptoglobin is a positive acute-phase protein, meaning its levels increase in response to inflammation . It sequesters iron within hemoglobin, preventing iron-utilizing bacteria from benefiting from hemolysis . Reduced levels of haptoglobin are observed in hemolytic anemias and impaired liver function, while high levels indicate acute or chronic inflammation .

Haptoglobin levels are used as a diagnostic marker for various conditions. Low levels can indicate hemolysis or liver dysfunction, while high levels are associated with inflammation . Additionally, mutations in the haptoglobin gene can lead to conditions such as ahaptoglobinemia or hypohaptoglobinemia . Haptoglobin is also linked to diabetic nephropathy, coronary artery disease in type 1 diabetes, Crohn’s disease, primary sclerosing cholangitis, and a reduced incidence of Plasmodium falciparum malaria .