Protein A (Protein A) ELISA Kit (E-EL-0181)

This ELISA kit uses the Sandwich-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with an antibody specific to Protein A . Standards or samples are added to the micro ELISA plate wells and combined with the specific antibody. Then a biotinylated detection antibody specific for Protein A and Avidin-Horseradish Peroxidase (HRP) conjugate are added successively to each micro plate well and incubated. Free components are washed away. The substrate solution is added to each well. Only those wells that contain Protein A , biotinylated detection antibody and Avidin-HRP conjugate will appear blue in color. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm. The OD value is proportional to the concentration of Protein A . You can calculate the concentration of Protein A in the samples by comparing the OD of the samples to the standard curve.

Protein A is a cell wall protein isolated from Staphylococcus aureus type A. It has the property of binding to immunoglobulins at sites other than the antigen-binding sites and can form complexes containing protein A, antibodies and antigens. It is produced from wet bacterial suspension. It can bind to the Fc segments of most human IgG types (except IgG3), but rarely or almost not with human IgM. It is used in immunoassays and for the purification of IgG.