Endothelin Receptor A (extracellular) Blocking Peptide (#BLP-ER004) is the original antigen used for immunization during Anti-Endothelin Receptor A (extracellular) Antibody (#AER-004) generation. The blocking peptide binds and ‘blocks’ Anti-Endothelin Receptor A (extracellular) primary antibody, this makes it a good negative reagent control to help confirm antibody specificity in western blot and immunohistochemistry applications. This control is also often called a pre-adsorption control.