Streptavidin labeled with horseradish peroxidase. Streptavidin is a protein isolated from the bacterium Streptomyces avidinii and has no carbohydrate moieties. It has a molecular weight of approximately 60,000 daltons with an isoelectric point of 5. Product is in liquid form. KPL Peroxidase-labeled streptavidin is ideally suited ELISA, blotting, immunohistochemistry, and in situ hybridization applications.