Streptavidin is a 52-66 kDa (average 60 KDa) (subunit MW 14 kDa) biotin-binding protein isolated from Streptomyces avidini. Streptavidin is superior to avidin, because it does not contain carbohydrate like avidin and has no net charge at neutral pH. Streptavidin~biotin system is routinely used in Immunohistochemistry (IHC).
Buffer:
The conjugate (one mg of streptavidin conjugated with peroxidase) is supplied in one ml of 10 mM PO4, 200 mM NaCl, pH 7.5, BSA 10 mg/ml and 0.05% Proclin 300.