Numerous methods have been published for the detection of protein using avidin–biotin technology. Complications can arise using this system when the protein of interest is in extremely high or low abundance. The ability to successfully detect high- or low-abundance proteins is dependent on the detection system selected. The expression of endogenous biotinylated proteins in rat liver homogenate will be used to illustrate the methods utilized for the detection of high- and low-abundance proteins on a membrane. The advantages and disadvantages of enzymatic and direct fluorescence detection systems are discussed.
