Detection of Blotted Proteins: Not All Blockers Are Created Equal.

Western blotting is a standard analytical technique for detection of proteins. It is dependent on a number of components; from the specificity of the primary antibody to the reduction of competing biomolecules present in the assay. Blocking agents are a critical component for western blotting protocols as these diminish nonspecific binding by blocking off-target sites on the membrane. A variety of blocking agents are available and these are selected in an empirical manner, as no single blocker is compatible with every system. The best blocking agent and method for any particular assay will be an optimized but not absolute choice. Here, we describe characteristics of the most common blocking agents used in western blotting and discuss their advantages and disadvantages.