The E. coli in vivo Biotinylation Kit (with BirA Competent Cells) 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 a resistance gene for streptomycin or spectinomycin. This kit contains sufficient reagents, including BL21 cells, to express and label 10 x 1 L of E. coli culture.

Start by transforming the competent cells with a vector expressing your protein of interest linked to an AviTag™ sequence (for example: pAN or pAC vectors). After transformation, BirA expression is induced by IPTG and biotin is added to the culture. BirA efficiently catalyzes the specific attachment of biotin to the AviTag™.