Hemopexin (HPX)

hemopexin (or haemopexin) binds heme with the highest affinity of any known protein. Its function of scavenging the heme released or lost by the turnover of heme proteins such as hemoglobin and thus protects the body from the oxidative damage that free heme can cause. In addition, hemopexin releases its bound ligand for internalisation upon interacting with a specific receptor situated on the surface of liver cells. This function of hemopexin is to preserve the body's iron. Its levels in serum reflect how much heme is present in the blood. Therefore, high hemopexin levels indicates that there has been significant degradation of heme containing compounds and hemopexin is made to scavenge any heme it can. High hemopexin levels are therefore one of the diagnostic features of a hemolytic anemia.