HP

Fig1. Hp phenotype distribution affects the clinical value of Hp glycopeptides.

What is HP protein?

HP (Haptoglobin) is a protein coding gene which situated on the long arm of chromosome 16 at locus 16q22. This gene encodes a preproprotein which is processed to yield both alpha and beta chains, which subsequently combine as a tetramer to produce haptoglobin. Multiple transcript variants encoding different isoforms have been found for this gene. Haptoglobin protein is a secreted protein which is expressed by the liver and secreted in plasma. The Haptoglobin protein is consisted of 406 amino acids and its molecular mass is approximately 45.2 kDa.

What is the function of HP protein?

Haptoglobin is found to bind free plasma hemoglobin, which allows degradative enzymes to gain access to the hemoglobin, while at the same time preventing loss of iron through the kidneys and protecting the kidneys from damage by hemoglobin. Haptoglobin also acts as an antioxidant, has antibacterial activity, and plays a role in modulating many aspects of the acute phase response. The uncleaved form of allele alpha-2 (2-2), known as zonulin, plays a role in intestinal permeability, allowing intercellular tight junction disassembly, and controlling the equilibrium between tolerance and immunity to non-self antigens.

HP Related Diseases

Mutations in this gene and/or its regulatory regions cause ahaptoglobinemia or hypohaptoglobinemia. This gene has also been linked to diabetic nephropathy, the incidence of coronary artery disease in type 1 diabetes, Crohns disease, inflammatory disease behavior, primary sclerosing cholangitis, susceptibility to idiopathic Parkinsons disease, and a reduced incidence of Plasmodium falciparum malaria.