Haptoglobin
Haptoglobin is produced in the liver and secreted into the blood, where it attaches to any "free" hemoglobin; that is, hemoglobin not contained within red blood cells. Haptoglobin is an acute phase protein used for the detection of in vivo hemolysis. The primary function of haptoglobin is the irreversible binding of free oxyhemoglobin in plasma. This complex is then removed by the reticuloendothelial system. Thus, haptoglobin prevents loss of hemoglobin to urine and conserves iron. Elevated values are present in chronic and acute inflammatory and neoplastic diseases. Decreased levels can indicate liver disease, hemolytic anemia, sickle cell anemia, and genetic haptoglobinemia.
Swiss-Prot Accession Number: P00738