Affinity chromatography purification of erythrocyte membrane proteins after selective labeling with trinitrobenzene sodium sulfonate

2,4,6-Trinitrobenzene sodium sulfonate may be used, under appropriate conditions, for specific surface labeling of erythrocyte plasma membranes. Trinitrophenylated ghost proteins are easily purified by reverse immunoadsorption using rabbit anti-dinitrophenyl antibodies covalently linked to Sepharose 4B. The advantages of a method that permits selective labeling of membrane molecules with a hapten and their purification by affinity chromatography are obvious. The possible applications of such a method in the investigation of the composition of plasma membranes are discussed.