Vector® Laboratories’ enzyme-conjugated avidin and streptavidin are produced with the highest specific activity enzymes in optimal ratios. Specific covalent linkages are chosen to provide stable, highly active conjugates. Horseradish peroxidase labeled Avidin D (Av-HRP), for ELISAs and Blots, is optimized for use in solid-phase assays such as ELISAs and blotting applications. For HRP Avidin conjugate that is optimized for tissue/cell staining systems please see the following product: Avidin D, Horseradish Peroxidase (Av-HRP), Concentrate, for IHC