Transferrin ELISA

Transferrin is a metal-combining protein that reversibly binds to acid-soluble iron in plasma. It functions to transport iron to the bone marrow and to tissue storage organs such as the liver. Transferrin also participates in the regulation and control of iron absorption and protects against iron intoxication. Like haptoglobin, the carrier of hemoglobin, transferrin is synthesized in the liver; but unlike haptoglobin, transferrin is returned to the circulation after unloading its iron in the reticuloendothelial system.

In this assay, the transferrin present in samples reacts with the anti-transferrin antibodies which have been adsorbed to the surface of polystyrene microtiter wells. After the removal of unbound proteins by washing, anti-transferrin antibodies conjugated with horseradish peroxidase (HRP), are added. These enzyme-labeled antibodies form complexes with the previously bound transferrin. Following another washing step, the enzyme bound to the immunosorbent is assayed by the addition of a chromogenic substrate, 3,3’,5,5’-tetramethylbenzidine (TMB). The quantity of bound enzyme varies directly with the concentration of transferrin in the sample tested; thus, the absorbance, at 450 nm, is a measure of the concentration of transferrin in the test sample. The quantity of transferrin in the test sample can be interpolated from the standard curve constructed from the standards and corrected for sample dilution.