An enhanced ascorbate peroxidase 2/antibody-binding domain fusion protein (APEX2–ABD) as a recombinant target-specific signal amplifier

A recombinant target-specific signal amplifier was constructed by genetically fusing the enhanced ascorbate peroxidase 2 (APEX2) and an antibody-binding domain (ABD). The fusion protein APEX2–ABD possessed the peroxidase activity and the antibody-binding capability simultaneously and replaced the conventional HRP-conjugated secondary antibodies in a TSA assay for amplifying fluorescence signals.