Western blotting among the most frequently employed techniques used to detect proteins based on antigen-antibody interactions. The first step of western blotting is sample preparation; your protein of interest must be extracted from the tissue or cell culture it’s expressed in, protected from degradation, and prepared to be run on a gel. Boster provides products for sample preparation, including specialized extraction kits, lysis buffers, and protease inhibitors.
To extract a protein sample from a cell culture on solid medium, first rinse the culture with ice-cold PBS solution, then add ice-cold lysis buffer. Scrape adherent cells off the dish using a cold plastic scraper, or digest the cells with 0.05% trypsin. Once the cells are suspended, centrifuge the sample, draw off the supernatant fluid, and wash the pellet with ice cold PBS buffer. Re-suspend the cells in Boster mammalian cell protein extraction reagent and sonicate the solution for about 10-15 seconds, then lyse the cells with Boster RIPA lysis buffer and additional sonication. Centrifuge the sample to separate lipids and cellular debris from the soluble cell proteins, and aliquot the middle layer from the centrifuged sample into a fresh tube and store it at -20C.
The aliquots of cell lysis supernatant are ready for total protein quantification and gel electrophoresis.
For a detailed protocol of sample preparation starting with tissue samples, see our Western blot handbook.
For best results, select the right type extraction kit for your sample
If you observe weak signal, ghost bands, or inconsistent band sizes in your results, the source of error may be the protein extraction step. See our troubleshooting guides for more information