GLP1R (extracellular) Blocking Peptide (#BLP-GR021) is the original antigen used for immunization during Anti-GLP1R (extracellular) Antibody (#AGR-021) generation. The blocking peptide binds and ‘blocks’ Anti-GLP1R (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.