背景介绍 Biotin-labeling is commonly used for non-radioactive labeling and purification of proteins and other target molecules. Biotin labeling takes advantage of the exceptionally strong interaction between biotin (vitamin H) and either avidin or streptavidin. The affinity of biotin to avidin or streptavidin is one of the strongest known non-covalent interactions of a protein and ligand, exhibiting a dissociation constant (Kd) around 10-15. BirA protein ligase covalently adds biotin to biotin-acceptor peptides containing an AviTag™ sequence in a highly efficient and specific manner in a reaction that requires ATP. 产品介绍 The E. coli in vivo biotinylation kit comes in a convenient, easy-to-use format and contains all the components necessary to label biotin-acceptor peptides with biotin in E. coli. Strain BL21, a chemically competent E. coli B strain. The cells include an IPTG-inducible plasmid containing the BirA gene and the resistance gene for streptomycin or spectinomycin. Just transform the competent cells with a vector expressing your protein of interest with an AviTag™ sequence (example: pAN or pAC vectors). After transformation, BirA expression is induced and biotin is added to the culture. The BirA efficiently catalyzes the specific attachment of biotin to the AviTag.