Hepcidin 25 (bioactive)
Hepcidin is an iron homoeostasis regulator peptide. The bioactive peptide Hepcidin 25 is generated predominantly in the liver by proteolytic cleavage of the C-terminal 25 amino acids of prohepcidin. Subsequent N-terminal processing of Hepcidin 25 results in smaller peptides of 20-24 amino acids that show greatly reduced activity and accumulate in the urine.
Although originally identified as antimicrobial peptide, Hepcidin 25 is now established as a major regulator of dietary iron absorption and cellular iron release. Hepcidin exerts its regulatory function by counteracting the function of ferroportin, the major cellular iron exporter in the membrane of macrophages, hepatocytes, and the basolateral site of enterocytes. Hepcidin 25 induces the internalization and degradation of ferroportin, resulting in increased intracellular iron stores, decreased dietary iron absorption, and decreased circulating iron concentrations. Hepatocellular hepcidin synthesis decreases under conditions of increased demand for circulating iron like iron deficiency, hypoxia, anemia, and erythropoiesis. In contrast, hepcidin synthesis is induced by inflammation and infection.
The Hepcidin-25 manual and Hybrid assay are solid phase enzyme-linked immunosorbent assays based on the principle of competitive binding.
The microtiter wells are coated with monoclonal (mouse) antibody directed towards an antigenic site if the Hepcidin-25 molecule. Endogenous Hepcidin-25 of a patient sample competes with Hepcidin-25-biotin conjugate (Enzyme Conjugate) for binding to the coated antibody. Binding of the enzyme conjugate is detected by streptavidin-peroxidase. After addition of the substrate solution, the intensity of the color developed is inversely proportional to the concentration of the Hepcidin-25 in patient sample.