Excellent separation of proteins may very often be achieved rapidly and quite simply by zone electrophoresis in polyacrylamide gels. A major disadvantage of this method is the insolubility of the resultant gel, with the consequent difficulties in measuring both the quantities of prot,ein in the different fractions and the radioactivity associated with them. Fairbanks et al. ( 1) have described a procedure for slicing and drying disc electrophoresis gels so that radioautography may be employed for the localization of "C-labeled proteins. The autoradiographs are scanned with a densitometer to measure the relative amounts of radioactivity in each band. The protein is determined by densitometry scanaing of the stained geIs. Both determinations involve tedious integration for quantitation and very low efficiencies would be observed with tritiated proteins due to self absorption.
Maize1 (2) has designed an apparatus which effectively macerates cylindrical acrylamide gels by extruding them through a fine orifice so that separate fractions may be collected from one end of a gel to the other. Such a procedure might be applied to ]"H] protein fractions in a scintillation counting system but at a very low counting efficiency.
Young and Fulhorst (3) observed that polyacrylamide gels are soluble in 30% H,O, and this reagent has been used (4) to digest slices of polyacrylamide gels containing labeled proteins for radioactivity measurements. Although this technique greatly increases the sensitivity of the isotope measurement over the technique of Fairbanks et nl. (l), the peroxide destroys the protein-bound dye, preventing simultaneous estitnation of t,he relative protein content of the slices by way of the bound dye.