Tyramide signal amplification is an enzyme-mediated detection method that uses the catalytic activity of horseradish peroxidase (HRP) to generate high-density labeling of a target protein or nucleic acid sequence in situ. The TSA Kit #21 includes HRP—streptavidin and biotin-XX tyramide. The deposited biotin molecules can be detected with any of our avidin, streptavidin or neutravidin conjugates.