1. A procedure was devised that allows the membrane-skeletal proteins brain spectrin and ankyrin to be extracted selectively from a membrane-skeletal preparation, together with some actin, an Mr-103,000 protein and a population of glycoproteins. 2. Ankyrin-binding activities of the glycoproteins were investigated by affinity chromatography. We detected only one, Mr 205,000, that binds ankyrin and is prevented from binding by the cytoplasmic domain of Band 3, the established erythrocyte-membrane-binding site for ankyrin. The Mr-205,000 glycoprotein, designated ABGP205, may be a candidate for a membrane-binding site for ankyrin.
