Protein A is a surface protein (approximately 56kDa in size) originally discovered within the cell wall of Staphylococcus aureus. While important for bacterial survival, Protein A has beneficial uses in immunology for its high affinity binding to immunoglobulins (especially the IgG isotype). This high affinity property makes Protein A essential in the large scale purification of antibodies. Horseradish Peroxidase (HRP) is an enzyme that utilize organic peroxide compounds as electron donors. Naturally provides protection for plants against pathogens, but can be utilized in molecular biology to convert various substrates to detectable compounds (such as in Western Blotting and ELISAs).Synonyms: HRP, peroxidase, Horseradish peroxidase protein A