The primary plasma glycoprotein for binding free heme preventing oxidative toxicity and promoting iron recycling by the liver.
Role of protein in biology
Hemopexin is a plasma glycoprotein with the highest known binding affinity for free heme, functioning as a critical scavenger during intravascular hemolysis or cellular injury. Structurally, it comprises two β-propeller domains that form a high-affinity heme-binding pocket, enabling it to neutralize heme's oxidative toxicity and facilitate its transport to the liver for iron recycling via CD163 receptors. As an acute-phase reactant, hemopexin synthesis increases during inflammation, though chronic hemolysis often depletes its levels, exacerbating tissue damage.
Common research uses
Deficiencies or dysfunction in hemopexin are implicated in hemolytic anemias such as sickle cell disease and β-thalassemia, where unbound heme drives endothelial activation, vaso-occlusion, and organ damage. It also correlates with neurologic complications in familial epilepsy due to impaired heme clearance in neural tissues and contributes to sepsis-related mortality by failing to counteract hemoglobin-mediated inflammation. Therapeutically, hemopexin supplementation shows promise in preclinical models, reducing cardiovascular dysfunction in sickle cell mice by 50% and mitigating renal injury in hemolysis. It serves as both a biomarker for hemolytic severity and a potential therapeutic agent to attenuate heme toxicity in transfusion medicine, atherosclerosis, and acute porphyrias.
Common uses include metabolic studies, therapeutics research, IVD Assay standards, calibrators and controls, cardiovascular research, mass spectrometry, oxidative stress research, cell based assays.
