Practice question

Bovine serum albumin, a 66 kDa abundant plasma protein, is widely employed as blocking agent and antibody diluent in Western blotting and other immunoassays. At working concentration of 3 to 5 percent, BSA efficiently coats unoccupied membrane sites on PVDF or nitrocellulose without cross-reacting with most anti-mammalian antibodies, unlike milk which contains biotin and immunoglobulins that may interfere with certain detection systems. It provides gentle proteinaceous barrier, stabilizes diluted primary and secondary antibodies, reduces nonspecific electrostatic interactions, and maintains epitope accessibility, whereas Triton X-100 is detergent for permeabilization, SDS is denaturant, and TMB is substrate, not blocker.