B-PER® Bacterial Protein Extraction Reagent was developed for extraction of proteins, especially recombinant proteins,from bacteria (E. coli). The B-PER® Reagent has also been used for the extraction of recombinant proteins from insect cellsinfected by baculovirus. This reagent utilizes a proprietary, mild, nonionic detergent in 20 mM Tris•HCl (pH 7.5) for lysis ofthe bacterial cells. This method eliminates the need for mechanical disruption utilizing equipment that may not be availablein some research laboratories. The novel composition of this reagent provides versatility for different applications andeliminates exogenous contamination of the recombinant protein by the lysis reagent. Depending on the particular application,additional components such as lysozyme, protease inhibitors, salts, reducing agents, chelating agents, etc., may be added tothe reagent. The reagent may be used for both soluble protein extraction and inclusion body purification from total bacterialcell lysates.