HRP/AP-conjugated Secondary Antibodies

HRP/AP-conjugated secondary antibodies are detection reagents formed by conjugating horseradish peroxidase (HRP) or alkaline phosphatase (AP) to secondary antibodies. They enable high-sensitivity detection of target proteins via enzyme-catalyzed substrate reactions that generate chemiluminescent or chromogenic signals. HRP is the most widely used enzyme with high sensitivity; its substrates include ECL, DAB, and TMB for chemiluminescent or colorimetric detection. It is especially preferred to avoid interference from endogenous alkaline phosphatase in phosphoprotein samples. AP exhibits lower background and is ideal for phosphorylation detection or applications where HRP interference is a concern, using substrates such as BCIP/NBT or pNPP. These enzyme-conjugated secondary antibodies represent the gold standard for Western blot (HRP-ECL chemiluminescence), quantitative ELISA (HRP-TMB or AP-pNPP colorimetry), immunohistochemistry (HRP-DAB brown precipitate localization), and validation of immunoprecipitation.