Biotin-X Protein Labeling Kit

Binding of biotin by avidin, streptavidin or NeutrAvidin™ is the strongest known biological interaction with a dissociation constant in the range of 10-15 M. The vitamin biotin may be conjugated to many proteins without loss of their biological activity due to the small size of the biotin molecule. The biotinylated probe is usually detected by avidin, streptavidin or NeutrAvidin™, carrying a reporter group, e.g. horseradish peroxidase (HRP) or a fluorescent label. The protein of interest (POI) is often biotinylated at different positions. Each conjugated biotin binds one molecule of avidin, streptavidin or NeutrAvidin™, resulting in signal amplification. Biotin-X inserts a C6-spacer between the biotin and the protein molecule, hence reduces steric hindrance and increases accessibility for avidin, streptavidin or NeutrAvidin™. The interaction between biotin and biotin-binding proteins is used in various applications such as affinity chromatography, fluorescence-activated cell sorting (FACS), ELISA and Western Blot. This Protein Biotinylation Kit contains all reagents required for performing 5 separate labeling reactions of 5 mg of POI.