ISOLATION AND PURIFICATION OF A MACROMOLECULAR PROTEIN COMPONENT FROM HUMAN ERYTHROCYTE GHOST

1. 1.|A method is described for the isolation of a macromolecular protein component from intact human erythrocyte ghosts. This is done by the centrifugal removal of ghost fragments following distilled water dialysis and a freeze-thaw treatment. The protein is identified by electron microscopy using negative staining. It has the form of a hollow cylinder, which dissociates into torus structures. 2. 2.|The torus protein is purified by sucrose density gradient centrifugation and differential centrifugation. Purity is estimated by electron microscopy and polyacrylamide-gel electrophoresis. 3. 3.|The results are discussed in relation to the electron microscopic assessment of purity. It is considered that the hollow cylinder protein rather than the torus is the structure associated with the membrane of the intact ghost. The mild extraction procedure described releases only a small percentage of the ghost protein. It is less likely, however, to produce an alteration of the membrane proteins than the extraction methods that produce a high degree of protein solubilization. © 1969.